Japanese phonology


Japanese phonology[] is the system of sounds used in the pronunciation of the Japanese language. Unless otherwise noted, this article describes the standard variety of Japanese based on the Tokyo dialect.
There is no overall consensus on the number of contrastive individual sounds. Common approaches recognize at least 12 distinct consonants and 5 distinct vowels,. Phonetic length is contrastive for both vowels and consonants, and the total length of Japanese words can be measured in a unit of timing called the mora. Only limited types of consonant clusters are permitted. There is a pitch accent|pitch accent system] where the position or absence of a pitch drop may determine the meaning of a word:,, .
Japanese phonology has been affected by the presence of several layers of vocabulary in the language. In addition to native Japanese vocabulary, Japanese has a large amount of Chinese-based vocabulary and loanwords from other languages. Different layers of vocabulary allow different possible sound sequences.

Lexical strata

Many generalizations about the sound system of Japanese have exceptions when recent loanwords are taken into account. For example, the consonant generally does not occur at the start of native or Chinese-derived words, but it occurs freely in this position in mimetic and foreign words. Because of exceptions like this, discussions of Japanese phonology often refer to layers, or "strata," of vocabulary. The following four strata may be distinguished:

Yamato

Called or in Japanese, this category consists of inherited native vocabulary. Morphemes in this category show a number of restrictions on structure that may be violated by vocabulary in other layers.

Mimetic

Japanese possesses a variety of mimetic words that make use of sound symbolism to serve an expressive function. Like Yamato vocabulary, these words are also of native origin, and can be considered to belong to the same overarching group. However, words of this type show some phonological peculiarities that cause some theorists to regard them as a separate layer of Japanese vocabulary.

Sino-Japanese

Called in Japanese, words in this stratum originate from several waves of large-scale borrowing from Chinese that occurred from the 6th-14th centuries AD. They comprise 60% of dictionary entries and 20% of ordinary spoken Japanese, ranging from formal vocabulary to everyday words. Most Sino-Japanese words are composed of more than one Sino-Japanese morpheme. Sino-Japanese morphemes have a limited phonological shape: each has a length of at most two moras, which argue reflects a restriction in size to a single prosodic foot. These morphemes represent the Japanese phonetic adaptation of Middle Chinese monosyllabic morphemes, each generally represented in writing by a single Chinese character, taken into Japanese as kanji. Japanese writers also repurposed kanji to represent native vocabulary; as a result, there is a distinction between Sino-Japanese readings of kanji, called On'yomi, and native readings, called Kun'yomi.
The moraic nasal is relatively common in Sino-Japanese, and contact with Middle Chinese is often described as being responsible for the presence of in Japanese, although also came to exist in native Japanese words as a result of sound changes.

Foreign

Called in Japanese, this layer of vocabulary consists of non-Sino-Japanese words of foreign origin, mostly borrowed from Western languages after the 16th century; many of them entered the language in the 20th century. In words of this stratum, a number of consonant-vowel sequences that did not previously exist in Japanese are tolerated, which has led to the introduction of new spelling conventions and complicates the phonemic analysis of these consonant sounds in Japanese.

Consonants

Different linguists analyze the Japanese inventory of consonant phonemes in significantly different ways. recognizes only 12 underlying consonants, whereas recognizes 16, equivalent to Smith's 12 plus the following 4, and recognizes 21, equivalent to Smith's 12 plus the following 9. Consonants inside parentheses in the table can be analyzed as allophones of other phonemes, at least in native words. In loanwords, sometimes occur phonemically.
In some analyses, the glides/semivowels are not interpreted as consonant phonemes. In non-loanword vocabulary, they generally occur only in the sequences and, which are sometimes analyzed as rising diphthongs rather than as consonant-vowel sequences. analyzes the glides as non-syllabic variants of the high vowel phonemes, arguing that the use of vs. may be predictable if both phonological and morphological context is taken into account.

Phonetic notes

Details of articulation

Voice onset time

At the start of a word, the voiceless stops are slightly aspirated—less so than English stops, but more than those in Spanish. Word-medial seem to be unaspirated on average. Phonetic studies in the 1980s observed an effect of accent as well as word position, with longer voice onset time in accented syllables than in unaccented syllables.
A 2019 study of young adult speakers found that after a pause, word-initial may be pronounced as plosives with zero or low positive voice onset time ; while significantly less aspirated on average than word-initial, some overlap in voice onset time was observed. A secondary cue to the distinction between and in word-initial position is a pitch offset on the following vowel: vowels after word-initial start out with a higher pitch compared to vowels after, even when the latter are phonetically [|devoiced]. Word-medial are normally fully voiced, but may become non-plosives through lenition.

Lenition

The phonemes have weakened non-plosive pronunciations that can be broadly transcribed as voiced fricatives, although they may be realized instead as voiced approximants. There is no context where the non-plosive pronunciations are consistently used, but they occur most often between vowels:
These weakened pronunciations can occur after a vowel in the middle of a word, or when a word starting with follows a vowel-final word with no intervening pause. found that, as with the pronunciation of as vs., the use of plosive vs. non-plosive realizations of is closely correlated with the time available to a speaker to articulate the consonant, which is affected by speech rate as well as the identity of the preceding sound. All three show a high rate of plosive pronunciations after or after a pause; after, plosive pronunciations occur at high rates for and, but less frequently for, probably because word-medial after is often pronounced instead as a velar nasal . Across contexts, generally has a higher rate of plosive realizations than and.

Moraic consonants

Certain consonant sounds are called "moraic" because they count for a mora, a unit of timing or prosodic length. The phonemic analysis of [|moraic consonants] is disputed. One approach, particularly popular among Japanese scholars, analyzes moraic consonants as the phonetic realization of special "mora phonemes" : a mora nasal, called the hatsuon, and a mora obstruent consonant, called the sokuon. The pronunciation of these sounds varies depending on context: because of this, they may be analyzed as "placeless" phonemes with no phonologically specified place of articulation. A competing approach rejects the transcriptions and and the identification of moraic consonants as their own phonemes, treating them instead as the syllable-final realizations of other consonant phonemes.

Moraic nasal

The moraic nasal or mora nasal can be interpreted as a syllable-final nasal consonant. Aside from certain marginal exceptions, it is found only after a vowel, which is phonetically nasalized in this context. It can be followed by a consonant, a vowel, or the end of a word:
Its pronunciation varies depending on the sound that follows it.
  • Before a plosive, affricate, nasal, or liquid, it is pronounced as a nasal consonant assimilated to the place of the following consonant:
  • Before a vowel, approximant, or voiceless fricative, it is a nasalized vowel or moraic semivowel that can be broadly transcribed as . This pronunciation may also occur before the voiced fricatives, although more often, they are pronounced as affricates when preceded by the moraic nasal.
At the end of an utterance, the moraic nasal is pronounced as a nasal segment with a variable place of articulation and variable degree of constriction. Its pronunciation in this position is traditionally described and transcribed as uvular, sometimes with the qualification that it is, or approaches, velar after front vowels. Some descriptions state that it may have incomplete occlusion and can potentially be realized as a nasalized vowel, as in intervocalic position. Instrumental studies in the 2010s showed that there is considerable variability in its pronunciation and that it often involves a lip closure or constriction. A study of real-time MRI data collected between 2017 and 2019 found that the pronunciation of the moraic nasal in utterance-final position most often involves vocal tract closure with a tongue position that can range from uvular to alveolar: it is assimilated to the position of the preceding vowel, but the range of overlap observed between similar vowel pairs suggests this assimilation is not a categorical allophonic rule, but a gradient phonetic process. 5% of the utterance-final samples of the moraic nasal were realized as nasalized vowels with no closure: in this case, appreciable tongue raising was observed only when the preceding vowel was.
There are a variety of competing phonemic analyses of the moraic nasal. It may be transcribed with the non-IPA symbol and analyzed as a "placeless" nasal. Some analysts do not categorize it as a phonological consonant. Alternatively, it may be analyzed as a uvular nasal, based on the traditional description of its pronunciation before a pause. It is sometimes analyzed as a syllable-final allophone of the coronal nasal consonant, but this requires treating syllable or mora boundaries as potentially distinctive, because there is a clear contrast in pronunciation between the moraic nasal and non-moraic before a vowel or before :
Alternatively, in an analysis that treats syllabification as distinctive, the moraic nasal can be interpreted as an archiphoneme, since there is no contrast in syllable-final position between and.
Thus, depending on the analysis, a word like, pronounced phonetically as, could be phonemically transcribed as,, or.

Moraic obstruent

There is a contrast between short and long consonant sounds. Compared to singleton consonants, geminate consonants have greater phonetic duration. A geminate can be analyzed phonologically as a syllable-final consonant followed by a syllable-initial consonant and can be transcribed phonetically as two occurrences of the same consonant phone in sequence: a geminate plosive or affricate is pronounced with just one release, so the first portion of such a geminate may be transcribed as an unreleased stop. As discussed [|above], geminate nasal consonants are normally analyzed as sequences of a moraic nasal followed by a non-moraic nasal, e.g., =,. In the case of non-nasal consonants, gemination is mostly restricted by Japanese phonotactics to the voiceless obstruents /p t k s/ and their allophones.
Geminate consonants can also be phonetically transcribed with a length mark, as in, but this notation obscures mora boundaries. uses the length marker to mark a moraic nasal, as, based on the fact that a moraic consonant by itself has the same prosodic weight as a consonant-vowel sequence: consequently, Vance transcribes Japanese geminates with two length markers, e.g.,, and refers to them as "extra-long" consonants, on the grounds that there is no acoustic boundary between two halves of a geminate. In the following transcriptions, geminates will be phonetically transcribed as two occurrences of the same consonant across a syllable boundary, the first being unreleased.
A common phonemic analysis treats all geminate obstruents as sequences starting with the same consonant: a "mora obstruent", called the sokuon in Japanese, which can be phonemically transcribed with the non-IPA character. According to this analysis,,, are phonemically,,. This analysis seems to be supported by the intuition of native speakers and matches the use in kana spelling of a single symbol, a small version of the tsu sign to write the first half of any geminate obstruent. Some analyses treat as an underlyingly placeless consonant.
Another approach dispenses with and treats geminate consonants as double consonant phonemes, that is, as sequences consisting of a consonant phoneme followed by itself. According to this analysis,,, are phonemically,,. Alternatively, since the contrast between different obstruent consonants such as,, is neutralized in syllable-final position, the first half of a geminate obstruent can be interpreted as an archiphoneme.
It has been suggested that the underlying phonemic representation of the sokuon might be a glottal stop. The sound is used in certain marginal forms that can be interpreted as containing not followed by another obstruent. For example, can be found at the end of an exclamation, or before a sonorant in forms with emphatic gemination, and is used as a written representation of in these contexts. This suggests that Japanese speakers identify as the default form of, or the form it takes when it is not possible for it to share its place and manner of articulation with a following obstruent. According to this analysis,,, are phonemically,,.
Even if it can be phonemically analyzed as, the sokuon is not always phonetically glottal. A study by used a video recording system and observed no glottal constriction during the pronunciation of Japanese geminate consonants. These results stand in conflict with the impressionistic descriptions of some authors, such as, who ascribes glottal tension to the first half of geminate consonants. An acoustic study by reported some evidence of creaky voice being more frequent for vowels following geminate consonants in Japanese. concludes that the role of glottal tension in Japanese geminates requires further research.

Voiced affricate vs. fricative

The distinction between the voiced fricatives and the voiced affricates is neutralized in Standard Japanese and in most regional Japanese dialects.
In accents with the merger, the phonetically variable sound can be transcribed phonemically as, though some analyze it as, the voiced counterpart to. A 2010 corpus study found that in neutralizing varieties, both the fricative and the affricate pronunciation could be found in any position in a word, but the likelihood of the affricate realization was increased in phonetic conditions that allowed for greater time to articulate the consonant: voiced affricates were found to occur on average 60% of the time after, 74% after, and 80% after a pause. In addition, the rate of fricative realizations increased as speech rate increased. In terms of direction, these effects match those found for the use of plosive vs. non-plosive pronunciations of the voiced stops ; however, the overall rate of fricative realizations of seems to be higher than the rate of non-plosive realizations of.
As a result of the neutralization, the historical spelling distinction between these sounds has been eliminated from the modern written standard except in cases where a mora is repeated once voiceless and once voiced, or where rendaku occurs in a compound word: つく, いちける from. The use of the historical or morphological spelling in these contexts does not indicate a phonetic distinction: and in Standard Japanese are variably pronounced with affricates or fricatives according to the contextual tendencies described above, regardless of whether they are underlyingly voiced or derived by [|rendaku] from and.

Voiceless coronal affricate

In core vocabulary, can be analyzed as an allophone of before :
In loanwords, however, can occur before other vowels: examples include ; . There are also a small number of native forms with before a vowel other than, such as, although these are marginal and nonstandard. Based on dialectal or colloquial forms like these, as well as the phonetic distance between plosive and affricate sounds, argues that the affricate is its own phoneme, represented by the non-IPA symbol . In contrast, disregards such forms as exceptional, and prefers analyzing and as allophones of, not as a distinct affricate phoneme.

Palatalized consonants

Most consonants possess phonetically palatalized counterparts. Pairs of palatalized and non-palatalized consonants contrast before the back vowels, but are in complementary distribution before the front vowels: only the palatalized version occurs before, and only the non-palatalized version occurs before . Palatalized consonants are often analyzed as allophones conditioned by the presence of a following or. When this analysis is adopted, a palatalized consonant before a back vowel is interpreted as a biphonemic /Cj/ sequence. The phonemic analysis described above can be applied straightforwardly to the palatalized counterparts of, as in the following examples:
The palatalized counterpart of is normally described as :
In the analysis presented above, a sequence like is interpreted as containing three phonemes,, with a complex onset cluster of the form. Palatalized consonants could instead be interpreted as their own phonemes, in which case is composed of +. A third alternative is analyzing ~ as rising diphthongs, in which case is composed of +. argues for the cluster analysis, noting that in Japanese, syllables such as show a longer average duration than their non-palatalized counterparts .
The glides cannot precede. The alveolar-palatal sibilants can be analyzed as the palatalized allophones of, but it is debated whether this phonemic interpretation remains accurate in light of contrasts found in loanword phonology.

Alveolo-palatal sibilants

The three alveolo-palatal sibilants function, at least historically, as the palatalized counterparts of the four coronal obstruents. Original came to be pronounced as, original came to be pronounced as, and original and both came to be pronounced as.
Likewise, original came to be pronounced as, original came to be pronounced as, and original and both came to be pronounced as :
Therefore, alveolo-palatal can be analyzed as positional allophones of before, or as the surface realization of underlying clusters before other vowels. For example, can be analyzed as and as. Likewise, can be analyzed as and as. Most dialects show a merger in the pronunciation of underlying and before or, with the resulting merged phone varying between and. The contrast between and is also neutralized before in most dialects.
While the diachronic origins of these sounds as allophones of is uncontroversial, there is disagreement among linguists about whether alveolo-palatal sibilants continue to function synchronically as allophones of coronal consonant phonemes: the identification of as a palatalized allophone of is especially debated, due to the presence of a distinctive contrast between and in the foreign stratum of Standard Japanese vocabulary.

vs. foreign

The sequences are found exclusively in recent loanwords; they have been assigned the novel kana spellings ティ, ディ. Based on a study of type frequency in a lexicon and token frequency in a spoken corpus, concludes that and have become about as contrastive before as they are before. Some analysts argue that the use of in loanwords shows that the change of to is an inactive, 'fossilized' rule, and conclude that must now be analyzed as containing an affricate phoneme distinct from ; others argue that pronunciation of as continues to be an active rule of Japanese phonology, but that this rule is restricted from applying to words belonging to the foreign stratum.
In contrast to, the sequences are not established even in loanwords. English is still normally adapted as before . An example is from cinema. Likewise, English is normally adapted as before . Pronouncing loanwords with or is rare even among the most innovative speakers, but not entirely absent. To transcribe, as opposed to, it is possible to use the novel kana spelling スィ . The use of スィ and its voiced counterpart ズィ was mentioned, but not officially recommended, by a 1991 cabinet directive on the use of kana to spell foreign words. argues that the difference between and may be marginally contrastive for some speakers, whereas denies that are ever distinguished in pronunciation from in adapted forms, regardless of whether the spellings スィ and ズィare used in writing.
The sequence also has some marginal use in loanwords. An example is. In many cases a variant adaptation with exists.

Alternations involving

Aside from arguments based on loanword phonology, there is also disagreement about the phonemic analysis of native Japanese forms. Some verbs can be analyzed as having an underlying stem that ends in either or ; these become or respectively before inflectional suffixes that start with :
In addition, notes that in casual speech, or in verb forms may undergo coalescence with a following, forming and respectively, as in for 'if lend' and for 'if win.' On the other hand, per, can occur instead of for some speakers in contracted speech forms, such as for 'saying', for 'if one waits', and for 'if one speaks'; Vance notes these could be dismissed as non-phonemic rapid speech variants.
argues that alternations in verb forms do not prove is phonemically, citing kawanai vs. kai, kau, kae, etc. as evidence that a stem-final consonant is not always maintained without phonemic change throughout a verb's conjugated forms, and ~ ' read' as evidence that palatalization produced by vowel coalescence can result in alternation between different consonant phonemes.

Competing phonemic analyses

There are several alternatives to the interpretation of as allophones of before or.
Some interpretations agree with the analysis of as an allophone of and as an allophone of, but treat as the palatalized allophone of a voiceless coronal affricate phoneme . In this sort of analysis, =.
Other interpretations treat as their own phonemes, while treating other palatalized consonants as allophones or clusters. The status of as phonemes rather than clusters ending in is argued to be supported by the stable use of the sequences in loanwords; in contrast, is somewhat unstable, and other consonant + sequences such as, are generally absent.
It has alternatively been suggested that pairs like vs. could be analyzed as vs.. objects to analyses like on the basis that the sequence is otherwise forbidden in Japanese phonology.

Voiceless bilabial fricative

In core vocabulary, the voiceless bilabial fricative occurs only before. In this context, can be analyzed as an allophone of. Examples include and, which can be phonemically transcribed as,. Some descriptions of Japanese phonetics state that the initial sound of is not consistently produced as, but is sometimes a sound with weak or no bilabial friction that could be transcribed as .
In loanwords, can occur before other vowels or before. Examples include,,,, and . Because of loanwords like these, the consonant is distinguished from before, as in the minimal pair and from English fork and hawk; likewise, is distinguished from before. Even in loanwords, is not distinguished from before : for example, English hood and food are both adopted as Japanese .
The integration of,,, and into contemporary spoken Standard Japanese seems to have been completed at some point after the middle of the twentieth century, in the post-war period: before then, these sequences of sounds seem to have been commonly used only in educated pronunciation. Loanwords borrowed more recently than around 1890 fairly consistently show as an adaptation of foreign. Some older borrowed forms show adaptation of foreign to Japanese before a vowel other than, such as and.
Another old adaptation pattern replaced foreign with before a vowel other than, e.g. film > . Both of these replacement strategies are largely obsolete nowadays, although certain old adapted forms continue to be used, sometimes with specialized meanings compared to a variant pronunciation: for example, tends to be restricted in modern use to photographic films, whereas is used for other senses of "film" such as movie films.

Voiced bilabial fricative

Spellings with the kana have been used in narrow transcriptions into Japanese, in an attempt to render a voiced labiodental fricative,, in other languages, which most Japanese speakers find difficult. The actual pronunciation of a foreign "v sound" is normally not distinguished from a Japanese : for example, there is no meaningful phonological or phonetic difference in pronunciation between and, or between and considers an attempt at rendering to be a "foreignism," in other words, if an innovative Japanese speaker tries to pronounce it, they are treating it as part of a foreign word, rather than of a word that is fully integrated into Japanese lexicon. According to and, the foreign is realized in Japanese as a voiced bilabial fricative,, which already exists as an allophone of in the Yamato and Sino-Japanese strata, although it "seems to be much less fricative than the corresponding Castillan Spanish sound in lobo for instance". Thus, can be phonetically transcribed as. Irwin is non-committal on the phonemic status of. suggests a different realization, a "voiced labiodental spirant," thus, which is questioned by and rejected by. Depending on the source language, a foreign "v sound" can alternatively be rendered as b, v or w.

Velar nasal onset

For some speakers, the velar nasal can occur as an onset in place of the voiced velar plosive in certain conditions. Onset, called, is generally restricted to word-internal position, where it may occur either after a vowel or after a moraic nasal . It is debated whether onset constitutes a separate phoneme or an allophone of. They are written the same way in kana, and native speakers have the intuition that the two sounds belong to the same phoneme.
Speakers can be divided in three groups based on the extent to which they use in contexts where is not required: some consistently use, some never use, and some show variable use of versus . Speakers who consistently use are a minority. The distribution of versus for these speakers mostly follows predictable rules : however, a number of complications and exceptions exist, and as a result, some linguists analyze as a distinct phoneme for consistent nasal speakers. The contrast has very low functional load, but it is possible to find or construct some pairs of words that are segmentally identical aside from the use of versus for consistent nasal speakers, such as versus . Another commonly cited pair is versus, although aside from the segmental difference in the consonant, these are prosodically distinct: the first is normally pronounced as two accent phrases,, whereas the second is pronounced as a single accent phrase.

Distribution of vs.

At the start of an independent word, all speakers use in almost all circumstances. However, postpositional particles, such as the subject marker, are pronounced with by consistent nasal speakers. In addition, a few words may be pronounced with even when they occur at the start of an utterance: examples include the conjunction and the word.
In the middle of a native morpheme, consistent nasal speakers always use. But in the middle of foreign-stratum morphemes, may be used even by consistent nasal speakers. It is also possible for foreign morphemes to be pronounced with medial : there is considerable variability, but this may be more common in older borrowings or in borrowings that contained in the source language.
At the start of a morpheme in the middle of a word, either or may be possible, depending on the word. Only is possible after the honorific prefix or at the start of a reduplicated mimetic morpheme. Consistent nasal speakers typically use at the start of the second morpheme of a bimorphemic Sino-Japanese word, or at the start of a morpheme that has undergone rendaku. In cases where the second morpheme in a compound starts with when used independently, the compound might be pronounced with either or by consistent nasal speakers: factors such as the lexical stratum of the morpheme may play a role, but it seems difficult to establish precise rules predicting which pronunciation occurs in this context, and the pronunciation of some words varies even among consistent nasal speakers, such as .
The morpheme, is pronounced with when it is used as part of a compound numeral, as in, although 五 can potentially be pronounced as when it occurs non-initially in certain proper nouns or lexicalized compound words, such as 為五郎, 七五三, or 十五夜.
To summarize:

Sociolinguistics of

The frequency of onset in Tokyo Japanese speech was falling as of 2008, and seems to have already been on the decline in 1940. Pronunciations with are generally less frequent for younger speakers, and even though the use of was traditionally prescribed as a feature of standard Japanese, pronunciations with seem in practice to have acquired a more prestigious status, as shown by studies that find higher rates of usage when speakers read words from a list. The frequency of also varies by region: it is rare in the southwestern Kansai dialects, but more common in the northeastern Tohoku dialects, with an intermediate frequency in the Kanto dialects.

Vowels

FrontCentralBack
Close
Mid
Open

  • is central. shows a fronter quality,, while shows a backer quality,.
  • are mid.
  • is a close near-back vowel with the lips unrounded or compressed. When compressed, it is pronounced with the side portions of the lips in contact but with no salient protrusion. In conversational speech, compression may be weakened or completely dropped. It is centralized after and palatalized consonants, and possibly also after. In contradiction to the preceding descriptions, characterize as rounded and propose that the transcription is more accurate than, while acknowledging the possibility of unrounding in fast speech. Based on visual recordings of Japanese speakers' lips, they conclude that is pronounced with lip protrusion, in contrast to the spread lip position of a vowel like, or the vertical movement of the lips towards each other for the allophone of. They suggest that the perceptual impression of Japanese as an unrounded vowel could be caused partly by its fronted articulation, and partly by its protrusion being accompanied by less vertical lip closure compared to in other languages, resulting in a less rounded sound. Lip protrusion was also found to be greater for Japanese than for in a 2005 MRI study and in a 1997 study using x-ray microbeam kinematic data. A 2012 study using electromagnetic tracking observed Japanese to have greater lip protrusion in angry or sad emotional contexts than in emotionally neutral speech.
  • All vowels are more centralized in prose than in individual words. The more careful the pronunciation, the less centralized the vowels are.

Long vowels and [|vowel sequences]

All vowels display a length contrast: short vowels are phonemically distinct from long vowels:
Long vowels are pronounced with around 2.5 or 3 times the phonetic duration of short vowels, but are considered to be two moras long at the phonological level. In normal speech, a "double vowel", that is, a sequence of two identical short vowels, is pronounced the same way as a long vowel. However, in slow or formal speech, a sequence of two identical short vowels may be pronounced differently from an intrinsically long vowel:
In the above transcriptions, represents hiatus between two identical vowels at morpheme boundaries. In the waveforms of carefully pronounced samples, a slight "dip in intensity" has been observed at the morpheme boundary between sato and oya in, but not in where such a boundary is not present. There is disagreement as to what causes this dip. describes it as "a diminution in loudness between the two vowels and a renewed pulse of expiration on the second." says that it is a "glottal stop", which the author considered a phoneme, and that "this phoneme also represents the glottal constriction associated with vowel rearticulation." says it can be "a pause or a light glottal stop". Both Martin and Labrune adopt the transcription, a superscript glottal stop letter. Vance, following Martin, used the term "vowel rearticulation" and transcribed it as at first, but now adopts . Vance's notion of "vowel rearticulation" has been criticized for citing Bloch's spurious phonetic description without proposing an alternative, such as whether palatal or labial glides can separate two identical vowels across morpheme boundaries, as in and. Given that the voicing of the vowels, facilitated by the vibration of the vocal folds, is not interrupted during hiatus, states that there is no complete glottal closure, questions whether there is any actual glottal narrowing at all, and notes that the articulation of the second vowel in involves slight labial narrowing. However, full glottal stops have been found to occur through acoustic analyses, albeit seldom in individual words and much less commonly even in slowly read sentences.
In fast speech, a sequence of two identical short vowels may fuse into one long vowel. This applies not only to and, but also to any two identical vowels straddling morpheme or word boundaries:,,,,.
A double vowel may bear pitch accent on either the first or second element, whereas an intrinsically long vowel can be accented only on its first mora. The distinction between double vowels and long vowels may be phonologically analyzed in various ways. One analysis interprets long vowels as ending in a special segment that adds a mora to the preceding vowel sound. Another analysis interprets long vowels as sequences of the same vowel phoneme twice, with double vowels distinguished by the presence of a "zero consonant" or empty onset between the vowels. A third approach also interprets long vowels as sequences of the same vowel phoneme twice, but treats the difference between long and double vowels as a matter of syllabification, with the long vowel consisting of the phonemes pronounced in one syllable, and the double vowel consisting of the same two phonemes split between two syllables.
Any pair of short vowels may occur in sequence. Sequences of three or more vowels also occur. Similar to the distinction between long vowels and double vowels, some analyses of Japanese phonology recognize a distinction between diphthongs and heterosyllabic vowel sequences; other analyses make no such distinction.
For certain verbs and adjectives with predictable accent locations, whether to phonologically analyze a sequence of two identical vowels as two separate vowels or a single continuous long vowel is a matter of convention, preference or accentual rules. For example, most accented verbs are predictably accented on the penultimate mora: thus is considered to have one long vowel if unaccented, as in, but two separate vowels if accented, as in. However, and are always accented on their antepenultimate mora, and this seemingly irregular location is attributed to a leftward accent shift to avoid accenting the special mora, which is almost always unaccentable and has been termed "deficient". Thus, these two verbs are said to have single long vowels, as in and.
Like accented verbs, most accented adjectives are also predictably accented on the penultimate mora, but for, some speakers accent the antepenultimate mora, pronouncing it as with a long vowel, while others accent the penultimate mora, pronouncing it as with two short sounds. Other forms of this verb, such as, are accented on the antepenultimate mora in the conservative variety of Tokyo Japanese, and accented on the penultimate mora in the innovating variety. On the other hand, while and are both unaccented and said to have one long vowel, is accented and has two vowels because of an accentual rule that applies to all unaccented adjectives followed by the particle. conservatively has two vowels and innovatingly has one long vowel because of the different rule-based locations of the accent in the two varieties. Overall, in these particular cases, whether a double is treated as one long vowel or two vowels depends ad hoc on whether the second is accented.
As noted above, adjectival forms ending in are accented conservatively on the antepenultimate mora and innovatingly on the penultimate one. Yet for, the recommended patterns are conservatively on the preantepenultimate mora, as in, and innovatingly on the penultimate one,. In both cases, accentuating the antepenultimate mora is avoided and it maintains its status as the lengthening mora. The antepenultimate-accented pattern,, with two identical vowels rather than one long vowel, has not been widely recommended, although at least one source has claimed it is plausible. The antepenultimate mora of is similarly maintained as in two patterns: conservative and innovating. On the other hand, in, the two vowels result from a reduplication of the morpheme, therefore have a morpheme boundary between them, and the conservative pattern is simply.
forms historically can lose the consonant, which gives rise to long vowels by means of vowel fusion, as in →. These forms are found in non-Tokyo dialects, as well as in "super-polite" adjectival expressions with in Tokyo Japanese, as in. When is used this way, the result would be, with a potentially triply long vowel. Phonetically, a bilabial glide has been said to be added, which would yield, on account of the same glide existing in, but the actual production of that glide, which does not normally occur before the vowel, by native speakers, is inconclusive. As for and, 16th-century transcriptions such as touô and vouô by European missionaries show that of the three 's, only the last two formed a long vowel. An Ōita dialect uses a different vowel quality for the last two vowels in these cases, roughly and, compared to the Tokyo and. The auxiliary probably has the same effect in some verbs, such as,,, whose stems used to contain a labial glide. It has been suggested that these cases of "triple o" may actually be pronounced as mere "double o".
There are other cases where losses of consonants also result in long vowels. In adjectives, completely disappeared from historical forms, resulting in forms such as,, etc. In verbs, the intervocalic labial fricative disappeared from historical forms, resulting in verbs like. Classical Japanese verbs, recited in the modern Tokyo accent, frequently contain long vowels at the end because of such forms, while their modern equivalents do not, for example, →, →. In some cases such as,, the centralizing effect of on the first, phonetically, may cause variation among speakers, some of whom have long vowels while others have a sequence of two short vowels; compare the noun, where only a long vowel is said to occur. In the case of, the fusion of the historical vowel sequence resulted in a long vowel, despite the kana spelling.

Devoicing

Japanese vowels are sometimes phonetically voiceless. There is no phonemic contrast between voiced and voiceless versions of a vowel, but the use of voiceless vowels is often described as an obligatory feature of standard Tokyo Japanese, in that it sounds unnatural to use a voiced vowel in positions where devoicing is usual. Devoicing mainly affects the short high vowels and when they are preceded by a voiceless consonant and followed by a second voiceless consonant or by a pause. These vowels are normally not devoiced if they are either preceded or followed by a voiced consonant or by another vowel, although occasional exceptions to this have been observed.

/i u/ between voiceless consonants or before a pause

In general, a high vowel between two voiceless consonants is very likely to be devoiced if the second consonant is a stop or affricate, or if the first is a stop and the second is a voiceless fricative other than.
Devoicing of and between voiceless consonants is not restricted to fast speech and occurs even in careful pronunciation. Devoicing is inhibited if the second consonant is and also if the second consonant is a fricative and the first consonant is a fricative or affricate. There is also a tendency to avoid devoicing both vowels when two consecutive syllables contain high vowels between voiceless consonants: nevertheless, it is possible for both vowels to be devoiced in this context. Some older descriptions state that the presence of [|pitch accent] on a mora inhibits devoicing of its vowel, but for young contemporary speakers, it seems to be possible to devoice accented vowels.
Avoidance of consecutive devoicing can be seen in pronunciations such as the following:
Devoicing can affect word-final or. A word-final high vowel is likely to be devoiced when it is preceded by a voiceless consonant and followed without pause by a word that starts with a voiceless consonant within the same phrase. A word-final high vowel may also be devoiced when preceded by a voiceless consonant and followed by a 'pause' at a phrase boundary. Devoicing between a voiceless consonant and a pause seems to occur with less overall consistency than devoicing between voiceless consonants. Final is frequently devoiced in the common sentence-ending copula and polite suffix. Phrase-final vowels are not devoiced when the phrase carries the rising intonation associated with an interrogative sentence, as in the question.

Atypical devoicing

A high vowel may occasionally be devoiced after a voiceless consonant even when the following sound is voiced. Devoicing in this context seems to occur more often before nasals or approximants than before other voiced consonant sounds. In particular, the final in desu and masu shows a relatively high devoicing rate before the particles yo and wa. Some studies have also found rare examples of voiceless vowels after voiced consonants. Per Vance 2008, high vowels are not devoiced next to a voiced segment in careful pronunciation.
The non-high vowels are sometimes devoiced, usually between voiceless consonants; devoicing of these vowels is infrequent, optional, varies between speakers, and can be affected by speech rate. In theory, must be unaccented, surrounded by voiceless consonants, and followed by the same vowel in the next mora in order to devoice. The least commonly devoiced vowel has been reported to be, although a 2005 study of a corpus of spontaneous speech found lower devoicing rates for ; it is unclear which vowel is actually least likely to devoice.

Phonetics of devoicing

A so-called "devoiced vowel" does not necessarily surface as a discrete acoustic segment. In some cases, especially after a fricative, it likely disappears altogether, with no identifiable separation between the consonant and the "vowel" at all. Despite its hiddenness, the "vowel" still rhythmically contributes to a full mora, and still exerts assimilatory effects on the consonant, namely palatalization for and lip compression or velarization for, hence the following realizations:
Phonetically, a devoiced vowel may sound similar or identical to a voiceless fricative: for example, the devoiced of kitai sounds like the voiceless palatal fricative. Sometimes there is no clear acoustic boundary between the sound of a devoiced vowel and the sound of the preceding voiceless consonant phoneme. For example, although the word is phonemically analyzed as starting with a consonant phoneme followed by a devoiced vowel phoneme, acoustically it may sound like it starts with a fricative that is sustained up until the following, with no third sound intervening between these two consonant sounds.
Some analysts have proposed that 'devoiced' vowels may actually be deleted in some circumstances, either at the phonetic level or at some level of the phonology. However, it has been argued in response that other phenomena show at least the underlying presence of a vowel phoneme:
  • Prosodically, vowel devoicing does not affect the mora count of a word.
  • Even when the vowel of a CV sequence is devoiced and appears to be deleted, the pronunciation of the preceding consonant phoneme shows coarticulatory effects.
  • When a vowel is devoiced between two identical voiceless fricatives, the result is typically not pronounced as a single long fricative. Instead, two acoustically distinct fricative segments are usually produced, although it may be difficult to describe the acoustic characteristics of the sound that separates them. In this context, alternative pronunciations involving a voiced vowel are more common than they are between other voiceless sounds. The contrast in pronunciation between a long fricative and a sequence of two identical fricatives separated by a devoiced vowel phoneme can be illustrated by pairs such as the following:

Sociolinguistics of devoicing

Japanese speakers are usually not even aware of the difference of the voiced and devoiced pair. On the other hand, gender roles play a part in prolonging the terminal vowel: it is regarded as effeminate to prolong, particularly the terminal as in.

Nasalization

Vowels are nasalized before the moraic nasal .

Glottal stop insertion

A glottal stop may occur before a vowel at the beginning of an utterance, or after a vowel at the end of an utterance. This is demonstrated below with the following words :
When an utterance-final word is uttered with emphasis, the presence of a glottal stop is noticeable to native speakers, and it may be indicated in writing with the sokuon っ, suggesting it is identified with the moraic obstruent . This is also found in interjections like and.
An attempt at producing a glottal stop may not be complete, which may result in a period of creaky voice and be characterized as a "near miss." As demonstrated by a token of, there's a "clean" glottal stop before the initial vowel, but a "near miss" at the end of the final vowel :.
Glottal stops have also been found medially between two identical vowels. See #Long vowels and vowel sequences.

Prosody

Moras

Japanese words have traditionally been analysed as composed of moras, a distinct concept from that of syllables. Each mora occupies one rhythmic unit, i.e. it is perceived to have the same time value. A mora may be "regular" consisting of just a vowel or a consonant and a vowel, or may be one of two "special" moras, and. A glide may precede the vowel in "regular" moras. Some analyses posit a third "special" mora,, the second part of a long vowel. In the following table, the period represents a mora break, rather than the conventional syllable break.
Thus, the disyllabic may be analyzed as, dissected into four moras:,,, and.
In English, stressed syllables in a word are pronounced louder, longer, and with higher pitch, while unstressed syllables are relatively shorter in duration. Japanese is often considered a mora-timed language, as each mora tends to be of the same length, though not strictly: geminate consonants and moras with devoiced vowels may be shorter than other moras. Factors such as pitch have negligible influence on mora length.

Pitch accent

Standard Japanese has a distinctive pitch accent system where a word can either be unaccented, or can bear an accent on one of its moras. An accented mora is pronounced with a relatively high tone and is followed by a drop in pitch, which can be marked in transcription by placing a downward-pointing arrow after the accented mora.
The pitch of other moras in the word is predictable. A common simplified model describes pitch patterns in terms of a two-way division between low- and high-pitched moras. Low pitch is found on all moras following the accented mora and usually also on the first mora of the accent phrase. High pitch is found on the accented mora and on non-initial moras up to the accented mora, or up to the end of the accent phrase if there is no accented mora.
Under this model, it is not possible to distinguish the pitch patterns of an unaccented phrase and a phrase with accent on the final mora: both show low pitch on the first mora and high pitch on every following mora. It is generally said that there is no audible difference between these two accentuation patterns. Nevertheless, there is a lexical distinction between unaccented words and words accented on the final mora, which is made apparent when the word is followed by further material within the same accent phrase. For example, even though there is no perceptible difference between and when pronounced in isolation, there is a clear contrast between and, where these words are followed by the case particle が.
The placement of pitch accent, and the lowering of pitch on an initial unaccented mora, show some restrictions that can be explained in terms of syllable structure. Accent cannot be placed on the second mora of a heavy (bimoraic) syllable. An initial unaccented mora isn't always pronounced with low pitch when it occurs as part of a heavy syllable. Specifically, when the second mora of an accent phrase is or, the first two moras are optionally either LH or HH. In contrast, when the second mora is the first two moras are LL. When the second mora is, initial lowering seems to apply as usual to the first mora only, LH. rejects the use of the syllable in descriptions of Japanese phonology and so explains these phenomena alternatively as a consequence of,, constituting "deficient moras", a term Labrune suggests can also encompass moras without an onset, with a devoiced vowel, or with an [|epenthetic vowel].
Different dialects of Japanese have different accent systems: some distinguish a greater number of contrastive pitch patterns than the Tokyo dialect, while others make fewer distinctions.

Feet

The bimoraic foot, a unit composed of two moras, plays an important role in linguistic analyses of Japanese prosody. The relevance of the bimoraic foot can be seen in the formation of hypocoristic names, clipped compounds, and shortened forms of longer words.
For example, the hypocoristic suffix -chan is attached to the end of a name to form an affectionate term of address. When this suffix is used, the name may be unchanged in form, or it may optionally be modified: modified forms always have an even number of moras before the suffix. It is common to use the first two moras of the base name, but there are also variations that are not produced by simple truncation:
Truncation to the first two moras:
From first mora, with lengthening:
With formation of a moraic obstruent:
With formation of a moraic nasal:
From two non-adjacent moras:
argues that the various kinds of modifications are best explained in terms of a two-mora 'template' used in the formation of this type of hypocoristic: the bimoraic foot.
Aside from the bimoraic foot as shown above, in some analyses monomoraic feet or trimoraic feet are considered to occur in certain contexts.

Syllables

Although there is debate about the usefulness or relevance of syllables to the phonology of Japanese, it is possible to analyze Japanese words as being divided into syllables. When setting Japanese lyrics to music, a single note may correspond either to a mora or to a syllable.
Normally, each syllable contains at least one vowel and has a length of either one mora or two moras ; thus, the structure of a typical Japanese syllable can be represented as V, where C represents an onset consonant, V represents a vowel, N represents a moraic nasal, Q represents a [|moraic obstruent], components in parentheses are optional, and components separated by a slash are mutually exclusive. However, other, more marginal syllable types may exist in restricted contexts.
The majority of syllables in spontaneous Japanese speech are 'light', that is, one mora long, with the form V.

Heavy syllables

"Heavy" syllables may potentially take any of the following forms:
  • VN
  • VQ
  • VR. May be analyzed either as a special case of VV with both V as the same vowel phoneme, or as ending in a vowel followed by a special chroneme segment.
  • V₁V₂, where V₁ is different from V₂. Sometimes notated as VJ.
Some descriptions of Japanese phonology refer to a VV sequence within a syllable as a diphthong; others use the term "quasi-diphthong" as a means of clarifying that these are analyzed as sequences of two vowel phonemes within one syllable, rather than as unitary phonemes. There is disagreement about which non-identical vowel sequences can occur within the same syllable. One criterion used to evaluate this question is the placement of pitch accent: it has been argued that, like syllables ending in long vowels, syllables ending in diphthongs cannot bear a pitch accent on their final mora. It has also been argued that diphthongs, like long vowels, cannot normally be pronounced with a glottal stop or vowel rearticulation between their two moras, whereas this may optionally occur between two vowels that belong to separate syllables. argues that only, and can be diphthongs, although some prior literature has included other sequences such as,,,, when they occur within a morpheme. argues against the syllable as a unit of Japanese phonology and thus concludes that no vowel sequences ought to be analyzed as diphthongs.
In some contexts, a VV sequence that could form a valid diphthong is separated by a syllable break at a morpheme boundary, as in 'well with a pulley' from 'wheel, car' and 'well'. However, the distinction between a heterosyllabic vowel sequence and a long vowel or diphthong is not always predictable from the position of morpheme boundaries: that is, syllable breaks between vowels do not always correspond to morpheme boundaries.
For example, some speakers may pronounce the word with a heterosyllabic sequence, even though this word is arguably monomorphemic in modern Japanese. This is an exceptional case: for the most part, heterosyllabic sequences of two identical short vowels are found only across a morpheme boundary. On the other hand, it is not so rare for a heterosyllabic sequence of two non-identical vowels to occur within a morpheme.
In addition, it seems to be possible in some cases for a VV sequence to be pronounced in one syllable even across a morpheme boundary. For example, is morphologically a compound of and ; despite the morpheme boundary between and in this word, they seem to be pronounced in one syllable as a diphthong, making it a homophone with. Likewise, the morpheme used as a suffix to form the dictionary form of an i-adjective is almost never pronounced as a separate syllable; instead, it combines with a preceding stem-final to form the long vowel, or with a preceding stem-final, or to form a diphthong.

Superheavy syllables

Syllables of three or more moras, called "superheavy" syllables, are uncommon and exceptional ; the extent to which they occur in Japanese words is debated. Superheavy syllables never occur within a morpheme in Yamato or Sino-Japanese. Apparent superheavy syllables can be found in certain morphologically derived Yamato forms as well as in many loanwords.
According to some accounts, certain forms listed in the above table may be avoided in favor of a different pronunciation with an ordinary heavy syllable. suggests there might be a strong tendency to reduce superheavy syllables to the length of two moras in speech at a normal conversational speed, saying that tooQta is often indistinguishable from toQta. again affirms the existence of a tendency to shorten superheavy syllables in speech at a conversational tempo, but stipulates that the distinctions between and ; and ; and and are clearly audible in careful pronunciation. Ito and Mester explicitly deny that there is a general tendency to shorten the long vowel of forms such as tootte in most styles of speech. accepts superheavy syllables ending in and but describes as hardly possible, stating that he and the majority of the informants he consulted judged examples such as to be questionably well-formed in comparison to.
It has also been argued that in some cases, an apparent [|superheavy syllable] might actually be a sequence of a light syllable followed by a heavy syllable.
argues that sequences are generally syllabified as, citing forms where pitch accent is placed on the second vowel such as,, . state that compounds formed from words of this shape often exhibit variable accentuation, citing guriꜜinsha~guriiꜜnsha,, and.
note that the pitch-based criterion for syllabifying VV sequences would suggest that Sendaiꜜkko is syllabified as Sen.da.ik.ko; likewise, reports a suggestion by Shin’ichi Tanaka that the accentuation tookyooꜜkko implies the syllable division -kyo.oQ-, although Ohta favors the analysis with a superheavy syllable based on intuitition that this word contains a long vowel and not a sequence of two separate vowels. Ito and Mester ultimately question whether the placement of pitch accent on the second mora really rules out analyzing a three-mora sequence as a single superheavy syllable.
The word rondonkko has a pronunciation where the pitch accent is placed on :. interprets here as its own syllable, separate from the preceding vowel, while stating that a variant pronunciation, with a superheavy syllable, also exists. Ito and Mester consider the syllabification ron.do.nk.ko implausible, and propose that pitch accent, rather than always falling on the first mora of a syllable, may fall on the penultimate mora when a syllable is superheavy. Per, the superheavy syllable in toꜜotta bears accent on its first mora.
Evidence for the avoidance of superheavy syllables includes the adaptation of foreign long vowels or diphthongs to Japanese short vowels before in loanwords such as the following:
There are exceptions to this shortening: seems to never be affected, and, although often replaced with in this context, can be kept, as in the following words:

Vowelless syllables

Some analyses recognize vowelless syllables in restricted contexts.

Phonotactics

Within a mora

Palatals

A Japanese syllable can start with the palatal glide or with a consonant followed by. These onsets normally can be found only before the back vowels.
Before, never occurs. All consonants are phonetically palatalized before, but do not contrast in this position with unpalatalized consonants: as a result, palatalization in this context can be analyzed as allophonic. In native Japanese vocabulary, coronal obstruent phones do not occur before, and in contexts where a morphological process such as verb inflection would place a coronal obstruent phoneme before, the coronal is replaced with an alveolo-palatal sibilant, resulting in alternations such as 'wait' vs. 'wait' or 'lend' vs. 'lend'. Thus, function in native vocabulary as the palatalized counterparts of coronal consonant phonemes. However, the analysis of alveolo-palatal sibilants as palatalized allophones of coronal consonants is complicated by loanwords. The sequences are distinguished from in recent loanwords and to a lesser extent, some speakers may exhibit a contrast in loanwords between and.
Before, was lost in the current standard language. The use of the mora in loanwords is inconsistent: adapted pronunciations with, such as イエローカード from English yellow card, continue to be used even for recent borrowings. In theory, pronunciations with can be represented by the spelling イェ, although it's not clear that the use of the spelling イェ necessarily corresponds to how speakers phonetically realize the sequence. Foreign may alternatively be adapted as in some cases. For some speakers, the optional, colloquial coalescence of certain other vowel sequences to can produce in native forms, such as .
As discussed above, the sequences do not occur in standard Japanese outside of foreign loanwords and a few marginal exclamations. There are no morphological alternations motivated by this gap, since no morphemes have an underlying form ending in. In borrowed words, has been consistently retained at all time periods, with very few exceptions. The sequences and have usually been retained in words borrowed more recently than around 1950, whereas words borrowed before that point may show depalatalization to and respectively, as seen in the 19th-century borrowed forms ゼリー from English jelly, ゼントルマン from English gentleman, and セパード from English shepherd.
The sequences occur only in recent loans, such as フュージョン, デュエット, テューバ from [|fusion], duet, tuba: they can be interpreted as in analyses where is not interpreted as.

Pre- consonants

Several Japanese consonants developed special phonetic values before. Though originally allophonic, some of these variants have arguably attained phonemic status because of later neutralizations or the introduction of novel contrasts in loanwords.
In core vocabulary, can be analyzed as an allophonic realization of. However, in words of foreign origin, the voiceless bilabial fricative can occur before vowels other than. This introduces a distinctive contrast between and ; therefore, recognizes as a distinct consonant phoneme, and interprets as phonemically, leaving * as a gap. In contrast, prefers the analysis and argues that in this context is distinct phonemically and sometimes phonetically from the found in foreign . In any case, and do not contrast before.
Outside of loanwords, and do not occur, because were affricated to before.
In dialects that show neutralization of the contrast, the merged phone can occur before as well as before. Thus, for these dialects, can be phonemically analyzed as, leaving as a gap.
In core vocabulary, the voiceless coronal affricate occurs only before the vowel ; thus can be analyzed as an allophonic realization of. Verb inflection shows alternations between and, as in 'win' and 'win'. However, the interpretation of as is complicated by the occurrence of before vowels other than in loanwords.
In addition, unaffricated are sometimes used in recent loanwords. They can be represented in kana by トゥ and ドゥ, which received official recognition by a cabinet notice in 1991 as an alternative to the use of or to adapt foreign. Forms where and can be found include the following:
Older loanwords from French display adaptation of as and of as :
argues that and remain "foreignisms" in Japanese phonology; they are less frequent than, and this has been interpreted as evidence that a constraint against * remained active in Japanese phonology for longer than the constraint against *.
In both old and recent loanwords, the epenthetic vowel used after word-final or pre-consonantal or is normally rather than . However, adapted forms show some fluctuation between and in this context, e.g. French estrade 'stage', in addition to being adapted as, has a variant adaptation.

Between moras

Special moras

If analyzed as phonemes, the moraic consonants and show a number of phonotactic restrictions.
=In general, the moraic nasal can occur between a vowel and a consonant, between vowels, or at the end of a word.
In Sino-Japanese vocabulary, can occur as the second and final mora of a Sino-Japanese morpheme. It may be followed by any other consonant or vowel. However, in some contexts Sino-Japanese morpheme-final may cause changes to the start of a closely connected following morpheme:
  • Within a bimorphemic Sino-Japanese word, is regularly replaced with after, as shown by the different pronunciation of 輩 in versus. This does not affect across word boundaries or across the juncture in the middle of a "complex compound" where the first or second element is a prosodic word composed of more than one Sino-Japanese morpheme: for example, remains unchanged in,, and.
  • Some words where is followed by a morpheme that starts in modern Japanese with a vowel or semivowel developed a pronunciation with a geminate nasal as the result of historic sound changes. Aside from these isolated exceptions, followed by a vowel is regularly pronounced without resyllabification in Sino-Japanese compounds.
  • A following is sometimes changed to ; this can be interpreted as a special case of the more general sound change of rendaku.
Although usually not found at the start of a word, initial can occur in some colloquial speech forms as a result of dropping of a preceding mora. In this context, its pronunciation is invariably assimilated to the place of articulation of the following consonant:
Initial may also be used in some loanword forms:
=The moraic obstruent generally occurs only between a vowel and a consonant in the middle of a word. However, word-initial geminates may occur in casual speech as the result of elision:
In native Japanese vocabulary, is found only before ; in other words, before voiceless obstruents other than. The same generally applies to Sino-Japanese vocabulary. In these layers of vocabulary, functions as the geminate counterpart of, due to the historical development of Japanese from Old Japanese. For example, the native Japanese verbs and form the compound verb.
found that in a Japanese newspaper corpus, was followed over 98% of the time by one of : however, there were also at least some cases where it was followed by.
Geminate is found only in recent loanwords, and rarely in Sino-Japanese or mixed compounds.
Voiced obstruents do not occur as geminates in Yamato or Sino-Japanese words. The avoidance of geminated voiced obstruents can be seen in certain morphophonological processes that produce voiceless but not voiced geminate obstruents: e.g. Yamato vs. and Sino-Japanese vs. .
However, voiced geminate obstruents have been used in words adapted from foreign languages since the 19th century. These loanwords can even come from languages, such as English, that do not feature gemination in the first place. For example, when an English word features a coda consonant preceded by a lax vowel, it can be borrowed into Japanese with a geminate; gemination may also appear as a result of borrowing via written materials, where a word spelled with doubled letters leads to a geminated pronunciation. Because these loanwords can feature voiced geminates, Japanese now exhibits a voice distinction with geminates where it formerly did not:
The most frequent geminated voiced obstruent is, followed by,,. In borrowed words, is the only voiced stop that is regularly adapted as a geminate when it occurs in word-final position after a lax/short vowel; gemination of and in this context is sporadic.
Phonetically, voiced geminate obstruents in Japanese tend to have a 'semi-devoiced' pronunciation where phonetic voicing stops partway through the closure of the consonant. This is due to the inherent difficulty in sustaining voicing with a prolonged closure on the oral tract, which causes air pressure to build up quickly behind the closure without anywhere to escape. Voiced geminates can be devoiced for as much as 60% of their closure time after a brief period of initial voicing, and are shorter than voiceless geminates; geminated voiced stops do not lenite into fricatives. claims is always realized as an affricate with a long stop closure, not as a plain fricative, while still notes for. High vowels are not devoiced after phonemically voiced geminates.
In some cases, voiced geminate obstruents can optionally be replaced with the corresponding voiceless geminate phonemes:
Phonemic devoicing like this has been argued to be conditioned by the presence of another voiced obstruent. Another example is doreddo ~ doretto 'dreadlocks'. attributes this to a less reliable distinction between voiced and voiceless geminates compared to the same distinction in non-geminated consonants, noting that speakers may have difficulty distinguishing them due to the partial devoicing of voiced geminates and their resistance to the weakening process mentioned above, both of which can make them sound like voiceless geminates.
A small number of foreign proper names have katakana spellings that would imply a pronunciation with, such as and. The phonetic realization of in such forms varies between a lengthened sonorant sound and a sequence of a glottal stop followed by a sonorant.
Aside from loanwords, consonants that cannot normally occur after may be geminated in certain emphatic variants of native words. Reduplicative mimetics may be used in an intensified form where the second consonant of the first portion is geminated, and this can affect consonants that otherwise do not occur as geminates, such as or . Adjectives may take an emphatic pronunciation where the second consonant is geminated and the following vowel is lengthened, as in naggaai <, karraai <, kowwaai <. Similarly, per, and can occur in emphatic pronunciations of and as and. A 2020 study of geminate production in mimetic forms found that emphatically lengthened could be pronounced either as a lengthened sonorant with uninterrupted voicing, or with some amount of laryngealization such as glottal stop insertion. Another noteworthy characteristic of emphatically lengthened consonants is the potential for a greater than two-way distinction in length.
Atypical + consonant sequences may also arise in truncated word forms and in forms produced as the outcome of word games:
However, there are also reversed argot forms that show replacement of with in contexts where would be atypical: e.g. 'trumpet' → ; 'brat' → ; 'guy' → ; 'bat' →.

Vowel sequences and long vowels

Vowel sequences with no intervening consonant occur in many contexts:
  • Any pair of vowels can occur in sequence across morpheme boundaries, or within a morpheme in foreign words.
  • The sequences can be found within a morpheme in indigenous or Sino-Japanese words. also includes, as in, and, as in.
  • Within a Sino-Japanese morpheme, the only vowel sequences that can normally be found are or . Sino-Japanese is historically derived from and may variably be realized phonetically as rather than as the long vowel.
When the first of two vowels in a VV sequence is higher than the second, there is often not a clear distinction between a pronunciation with hiatus and a pronunciation where a glide with the same frontness as the first vowel is inserted before the second: i.e., the VV sequences may sound like. For example, English gear has been borrowed into Japanese as, but an alternative form of this word is. Per, the sequences are not pronounced like. The sequence is not pronounced like, but it is sometimes replaced with : this change is optional in loanwords. Kawahara states that the formation of a glide between may be blocked by a syntactic boundary or by some morpheme boundaries.
Many long vowels historically developed from vowel sequences by coalescence, such as >. In addition, some vowel sequences in contemporary Japanese may optionally undergo coalescence to a long vowel in colloquial or casual speech.
Within words and phrases, Japanese allows long sequences of phonetic vowels without intervening consonants. Sequences of two vowels within a single word are extremely common, occurring at the end of many i-type adjectives, for example, and having three or more vowels in sequence within a word also occurs, as in. In phrases, sequences with multiple o sounds are most common, due to the direct object particle being realized as o and the honorific prefix, which can occur in sequence, and may follow a word itself terminating in an o sound; these may be dropped in rapid speech. A fairly common construction exhibiting these is. More extreme examples follow:

Distribution of consonant phonemes based on word position

In Yamato vocabulary, certain consonant phonemes, such as,, and voiced obstruents, tend to be found only in certain positions in a word. None of these restrictions applies to foreign vocabulary; some do not apply to mimetic or Sino-Japanese vocabulary; and certain generalizations have exceptions even within Yamato vocabulary; nevertheless, some linguists interpret them as still playing a role in Japanese phonology, based on the model of a "stratified" lexicon where some active phonological constraints affect only certain layers of the vocabulary. The gaps in the distribution of these consonant phonemes can also be explained in terms of diachronic sound changes.
The voiced obstruents occur without restriction at the start of Sino-Japanese and foreign morphemes, but usually do not occur at the start of Yamato words. However, suffixes or postposed particles starting with these sounds have been in use since Old Japanese, such as the case particle ga, and morphemes that underlyingly start with a voiceless obstruent often have allomorphs that start with a voiced obstruent in the context of rendaku. In addition, word-initial occur frequently in the mimetic stratum of native Japanese vocabulary, where they often function as sound-symbolic variants of their voiceless counterparts. Furthermore, some non-mimetic Yamato words start with voiced obstruents. In some cases, voicing seems to have had an expressive function, adding a negative or pejorative shade to a root. Initial voiced obstruents have also arisen in some Yamato words as the result of phonetic developments, such as loss of original word-initial high vowels or alteration of words that originally started with nasal consonants. Diachronically, the scarcity of word-initial voiced obstruents in native Japanese words seems to be a consequence of their origin from Proto-Japonic sequences involving a nasal phoneme followed by an obstruent phoneme, which developed to prenasalized consonants in Old Japanese.
Yamato and mimetic words almost never start with. In contrast, word-initial occurs without restriction in Sino-Japanese and foreign vocabulary.
In Yamato words, occurs only after, as a word-medial geminate . In Sino-Japanese words, occurs only after or, alternating with in other positions. In contrast, mimetic words can contain singleton, either word-initially or word-medially. Singleton also occurs freely in foreign words, such as,,.
The restricted distribution of is explained by historical sound changes that turned original into at the start of a word and between vowels. The glide was eventually lost before any vowel other than. The labial fricative could be found before all vowels up through Late Middle Japanese, but was eventually debuccalized to before and palatalized to before : after these changes, was found only before. In modern Japanese, are commonly analyzed as allophones of a phoneme. Therefore, original regularly evolved to modern Japanese at the start of a non-mimetic word, and to either or no consonant sound between vowels in the middle of a non-mimetic word. The few non-mimetic words where occurs initially include, although as a personal name it is still pronounced Fūtarō.
The phoneme is rarely found in the middle of a Yamato morpheme or in the middle of a mimetic root. In Yamato words, this gap results from the aforementioned change of original to, rather than, in intervocalic position. In mimetic words, intervocalic is also uncommon: therefore, proposes that the usual outcome of original in this context was, which seems to be disproportionately common as the second consonant of a mimetic root. Likewise, never occurs in the middle of a Sino-Japanese morpheme.

Epenthetic vowels

Words of foreign origin are systematically adapted to Japanese phonotactics by inserting an epenthetic vowel after a word-final consonant or between adjacent consonants. While is inserted after the majority of consonants, it is usual to use after and after . After the epenthetic vowel is often or, echoing the quality of the vowel before the consonant.
There are some deviations from the aforementioned patterns: for example, some older borrowings such as use after. The use of epenthetic vowels in these contexts is an established convention when using kana to transcribe foreign words or names.
Historically, Sino-Japanese morphemes developed epenthetic vowels after most syllable-final consonants. This is usually, in some cases : the identity of the epenthetic vowel is largely, although not completely, predictable from the preceding consonant and vowel. It is debated whether these vowels should be regarded as having epenthetic status in the phonology of modern Japanese. The use of epenthetic vowels in Sino-Japanese forms has undergone some changes over time: for example, the descriptions of Portuguese missionaries indicate that in previous stages of the language, Sino-Japanese morphemes could end in coda with no epenthetic vowel.

Morphophonology

Japanese morphology is generally agglutinative rather than fusional. Nevertheless, Japanese exhibits a number of morphophonological processes that can change the shape of morphemes when they are combined in compounds, derived words, or inflected forms of verbs or adjectives. Various forms of sandhi exist; the Japanese term for sandhi generally is.

Rendaku

In Japanese, sandhi is prominently exhibited in rendakuconsonant mutation of the initial consonant of a morpheme from unvoiced to voiced in some contexts when it occurs in the middle of a word. This phonetic difference is marked in the kana spelling of a word via the addition of dakuten, as in. In cases where this combines with the yotsugana mergers, notably and in standard Japanese, the resulting spelling is morphophonemic rather than purely phonemic.

Yamato gemination or prenasalization

Certain processes, such as onbin sound changes, have acted to produce voiceless geminates in Yamato words. Gemination can arise as the result of emphasis, compounding, or verb conjugation. In this context, sequences of a moraic nasal and a voiced consonant are found in place of voiced geminate obstruents, which do not occur in native Standard Japanese words.
For example, adverbs built from a mimetic root and the suffix -ri may display root-internal gemination, as in nikkori from niko 'smiling'. Adverbs derived from roots with voiced medial consonants exhibit forms with a moraic nasal in place of gemination, such as shonbori from shobo 'lonely', unzari from uza 'bored, disappointed', bon'yari from boya 'vague', and funwari from fuwa 'light'. Likewise, a moraic consonant often occurs between the emphatic prefix and a following consonant: its allomorphs and are in complementary distribution, with used before voiceless consonants and used elsewhere.
Another example where either a voiceless geminate or is formed depending on the voicing of the following consonant is the derivation of reduced, i.e. contracted, compound verbs. Japanese has a type of compound verb formed by placing the stem of one verb before another. If the first verb has a stem that ends in a consonant, the vowel is usually placed between the first and second verb stem. But in some compounds, this vowel can be omitted, resulting in the final consonant of the first verb stem being placed directly before the initial consonant of the second verb stem. When this happens, the first consonant assimilates to the second, producing a voiceless geminate if the second is voiceless, and a sequence starting with if the second is a voiced obstruent or nasal.
In verb conjugation, the voiceless geminate is produced when a verb root that underlyingly ends in,, or is followed by a suffix starting with, whereas is produced when a verb root that underlyingly ends in,, or is followed by a suffix starting with.

Sino-Japanese gemination

When the second mora of a Sino-Japanese morpheme is,, or and it is followed by a voiceless consonant, this mora is sometimes replaced by the sokuon っ, forming a geminate consonant:
  • 一 + 緒 = 一緒
  • 学 + 校 = 学校
Sino-Japanese morphemes ending in these moras remain unchanged when followed by a voiced consonant, and are usually unchanged when followed by a vowel.
  • 学 + 外 =
  • 別 + 宴 =
  • 学 + 位 =
Gemination can also affect Sino-Japanese morphemes that historically ended in and that now end in long vowels:
  • 法 + 被 = 法被, instead of hōhi ほうひ
  • 合 + 戦 = 合戦, instead of gōsen
  • 入 + 声 = 入声, instead of nyūshō
  • 十 + 戒 = 十戒 instead of jūkai
Most morphemes exhibiting this change derive from Middle Chinese morphemes ending in, or, which developed a prop vowel after them when pronounced in isolation but were assimilated to the following consonant in compounds.
Gemination occurs regularly in words consisting of two Sino-Japanese morphemes, but tends not to occur across the major boundary of a complex compound. However, there are some cases of gemination in this context.
The formation of a geminate also depends on the identity of the first and second consonant:

Renjō

Sandhi also occurs much less often in, where, most commonly, a terminal or on one morpheme results in or respectively being added to the start of a following morpheme beginning with a vowel or semivowel, as in. Examples:
;First syllable ending with :
  • 銀杏 : ぎん + あん → ぎん
  • 観音 : くゎん + おむ → くゎんむ → かん
  • 天皇 : てん + わう → てんう → てん
;First syllable ending with from original :
  • 三位 : さむ + ゐ → さむ → さん
  • 陰陽 : おむ + やう → おむゃう → おんょう
;First syllable ending with :
  • 雪隠 : せつ + いん → せっ
  • 屈惑 : くつ + わく → くっ

Vowel fusion


ArchaicModern


1


auxiliary verb
medial or final
medial or final,, ,,
any,, ,, 1


During Late Middle Japanese, multiple vowel changes took place. Notably, the vowel tended to fuse with another vowel that preceded it, creating a long vowel. These vowel fusions are not reflected in historical kana usage, particularly that for classical Japanese.
These historical changes are still germane to modern grammatical analysis and education. For example, the "volitional/tentative" auxiliary notably fused with the last vowel of a :
  • :
  • *(書かむ → 書かう → 書こう)
  • *(笑はむ → 笑わう → 笑おう)
  • :
  • *(む → う → う → よう)
  • *(む → う → う → よう)
  • :
  • *(せむ → せう → しょう → しよう)
  • The verb and its derivations:
  • *(あらむ → あらう → あろう)
  • *(ならむ → ならう → なろう)
  • *(だらむ → だらう → だろう)
  • *(たらむ → たらう → たろう)
  • *(なからむ → なからう → なかろう)
  • Other :
  • *(でせむ → でせう → でしょう)
  • *(ませむ → ませう → ましょう)
Thus, while the mizenkei is listed in inflection tables, a combination of it and the auxiliary u, dubbed "volitional form" or "tentative form", must still be learnt separately. Furthermore, results of the above fusions caused some mizenkei to disappear entirely. Dictionaries and grammar guides no longer list たら, だら, でせ and なから as, respectively, the mizenkei of た, だ, です and ない. Instead, たろ, だろ, でしょ and なかろ are perfunctorily used. This perfunctory listing may also extend to godan verbs as well, for example 書く may have "two" mizenkei, 書か and 書こ, so that it has enough vowels to justify the term godan.
In contemporary Japanese, sequences such as can fuse into in masculine speech. This particular fusion is associated with non-Tokyo dialects, as well as Tokyo's male and/or delinquent sociolects. Some examples include,,,,,, etc. This fusion does not straddle word boundaries, hence does not occur in or. It is also lexically restrictive and does not occur in such words as,,,, etc. The glides are said to not occur before in contemporary native Japanese, yet they may still be heard in and. At least some speakers are cognizant enough of this that they can spell 怖え in kana as. has some variants, ii ~ ī, ei and ē. The same dialects and sociolects also have ui become ī, as in. The sequences and undergo fusion only in adjective forms.

Onbin

Another prominent feature is. This refers to various historical sound changes that can be loosely described as showing reduction, lenition or coalescence. Alternations resulting from [|onbin] continue to be seen in some areas of Japanese morphology, such as the conjugation of certain verb forms or the form of certain compound verbs.
In some cases, onbin changes occurred within a morpheme, as in, which underwent two sound changes from earlier → → → .
One type of onbin caused certain onset consonants to be deleted, mainly before or, which created vowel sequences, or long vowels by coalescence of with the preceding vowel.
Another type of onbin resulted in the development of moraic consonants or in certain circumstances in native Japanese words.

Types

Types of onbin are named after their resulting mora. If the resulting mora is, the onbin is called ; if, ; if, ; and if,.
Historically, sokuonbin was triggered in verb conjugation when any of the morae in a was followed by the consonant . In such an environment, the high vowel was reduced, and the remaining consonant eventually assimilated with :
  • (取って)
  • (買って)
  • (言って)
Grammatical sokuonbin is found predominantly in eastern dialects, while western ones favor u-onbin triggered by the historical mora :
  • (買うて)
  • (言うて)
On the other hand, hatsuonbin was triggered when any of the morae in a ren'yōkei was followed by the consonant. Similar vowel reduction and consonant assimilation occurred:
  • (踏んで)
  • (呼んで)
  • (死んで)
In general, onbin can occur in the following historical environments:
  • i-onbin:
  • *When a ren'yōkei with the mora,, or rarely, was followed by :
  • **(書いて)
  • **(泳いで)
  • **(指いて)
  • *When the ren'yōkei of the verb was followed by :
  • **(行いて)
  • *When the mora in ren'yōkei and lost the consonant in certain honorific verbs:
  • **(仰い)
  • *When the historical of an adjective lost the consonant. This particular type of i-onbin resulted in what is now known to foreign learners as "-i adjectives":
  • **(熱い)
  • **(美しい)
  • *In certain verbs:
  • **(る)
  • *In certain nouns:
  • **()
  • u-onbin:
  • *When a ren'yōkei with the mora, or was followed by :
  • **(思うて)
  • **(呼うで)
  • **(病うで)
  • **(頼うだる)
  • *When the ren'yōkei of the verbs and were followed by, even in eastern dialects:
  • **(問うて)
  • **(請うて)
  • *When the of an adjective lost the consonant :
  • **(良う)
  • **(有り難う)
  • **(早う)
  • **(美しゅう)
  • *In certain nouns:
  • **()
  • **()
  • **()and in many other compounds of Old Japanese pi₁to₂
  • **()
  • *In the verb
  • **(言う)
  • Sokuonbin:
  • *When a ren'yōkei with the mora, or was followed by :
  • **(勝って)
  • **(有って)
  • **(食って)
  • *When the ren'yōkei of the verb was followed by :
  • **(行って)
  • *In certain nouns:
  • **()
  • **(追っ手)
  • **()
  • **(矢っ張り)
  • **(真っ白)
  • Hatsuonbin:
  • *When a ren'yōkei with the mora, or was followed by :
  • **(読んで)
  • **(飛んで)
  • **(死んで)
  • *In certain expressions formed with the particles and :
  • **(盛んに)
  • **(残んの雪)
  • *In certain nouns:
  • **()
  • **()
  • **(真ん中)

Polite adjective forms

The polite adjective forms exhibit a one-step or two-step sound change. Firstly, these use the continuative form,, which exhibits onbin, dropping the k as →. Secondly, the vowel may combine with the preceding vowel, according to historical sound changes; if the resulting new sound is palatalized, meaning, this combines with the preceding consonant, yielding a palatalized syllable.
This is most prominent in certain everyday terms that derive from an i-adjective ending in -ai changing to , which is because these terms are abbreviations of polite phrases ending in gozaimasu, sometimes with a polite o- prefix. The terms are also used in their full form, with notable examples being:
  • , from.
  • , from.
  • , from.
Other forms like this are found in polite speech, such as → and →.

Earlier domestic phonology

Descriptions of Japanese phonology during the late Edo period and Meiji era were based on fanqie, a method of analyzing Middle Chinese syllables into an initial and a final. For example, the word can be analyzed as containing the initial represented by the word which shares such initial, and the final represented by the word which shares such final. The characters, and are respectively known in Chinese as the, the and the. However, in Japanese, they were also called the "father character", the "mother character" and the "child character". The methods and terminology of Middle Chinese phonology were implemented in Japanese phonology, where it was said that a "father sound" combined with a "mother sound" to make a "child sound". For example, the "child sound" can be analyzed as containing the "father sound" and the "mother sound". Other concepts borrowed from Chinese phonology included:
  • "Clear sound": In Chinese phonology, a voiceless consonant. In Japanese phonology, either a or a, which is not spelt with the dakuten or the handakuten.
  • "Muddy sound": In Chinese phonology, a voiced consonant. In Japanese phonology, a mora spelt with the dakuten.
  • "Partly clear sound": In Chinese phonology, a voiceless aspirated consonant. In Japanese phonology, a mora spelt with the handakuten.
  • "Rushed sound": In Chinese phonology, a checked syllable. In Japanese phonology, a moraic obstruent.
  • "Open sound": In Chinese phonology, a syllable that does not contain the bilabial onglide . In Japanese phonology, a mora that does not contain the bilabial onglide; or a mora that contains the vowel ; or a mora that contains the long open-mid vowel in Late Middle Japanese.
  • "Closed sound": In Chinese phonology, a syllable whose rhyme contains the bilabial onglide . In Japanese phonology, a mora that contains the bilabial onglide; or a mora that contains one of the vowels ; or a mora that contains the long close-mid vowel in Late Middle Japanese.