Checked tone

A checked tone, commonly known by the Chinese calque entering tone, is one of the four syllable types in the phonology of Middle Chinese. Although usually translated as "tone", a checked tone is not a tone in the western phonetic sense but rather a type of syllable that ends in a stop consonant or a glottal stop. Separating the checked tone allows -p, -t, and -k to be treated as allophones of -m, -n, and -ng, respectively, since they are in complementary distribution. Stops appear only in the checked tone, and nasals appear only in the other tones. Because of the origin of tone in Chinese, the number of tones found in such syllables is smaller than the number of tones in other syllables. Chinese phonetics have traditionally counted them separately.
Final voiceless stops and therefore the checked "tones" have disappeared from most Mandarin dialects, spoken in northern and southwestern China, but have been preserved in southeastern Chinese branches like Nanjing Mandarin, Yue, Min, and Hakka.
According to Zhang Taiyan, an advocate of Old National Pronunciation, checked tone is a signature of Han culture. Tones are an indispensable part of Chinese literature, as characters in poetry and prose were chosen according to tones and rhymes for their euphony. This use of language helps reconstructing Old Chinese and Middle Chinese pronunciations since Chinese writing system is logographic, rather than phonetic.

Phonetics

From a phonetic perspective, the prototypical entering tone is simply a syllable ending with a voiceless stop that has no audible release: , and/or a glottal stop depending on the language variety. Middle Chinese has only the first three.
It is customarily called a tone regardless of whether a tonal distinction is possible in such syllables. In languages such as Early Middle Chinese and most varieties of Wu, such syllables do not have contrastive tones and are therefore phonologically toneless. In languages such as Cantonese or Hakka, a small number of tonal distinctions exist, which historically developed as a substitute for the lost Middle Chinese initial voicing.
Some Chinese varieties have innovated new final consonants from such historical syllables. A few dialects of Gan have . In some dialects of Cantonese and Gan, the final stop is voiced.

History

The voiceless stops that typify the entering tone date back to the Proto-Sino-Tibetan, the parent language of Chinese as well as the Tibeto-Burman languages. In addition, Old Chinese is commonly thought to have syllables ending in clusters,, and . Such clusters were later reduced to /s/, which, in turn, became and ultimately "departing tone" in Middle Chinese.
The first Chinese philologists began to describe the phonology of Chinese during the Early Middle Chinese period, under the influence of Buddhism and the Sanskrit language that arrived along with it. There were several unsuccessful attempts to classify the tones of Chinese before the establishment of the traditional four-tone description between 483 and 493. It is based on the Vedic theory of three intonations. The middle intonation, ', maps to the "level tone" ; the upwards intonation, ', to the "rising tone" ; the downward intonation, , to the "departing tone". The distinctive sound of syllables ending with a stop did not fit the three intonations and was categorised as the "entering tone", thus forming the four-tone system. The use of this system flourished in the Sui and Tang dynasties, during which the Qieyun rime dictionary was written.
Note that modern linguistic descriptions of Middle Chinese often refer to the level, rising and departing tones as tones 1, 2 and 3, respectively.
By the time of the Mongol invasion, the former final stops had been reduced to a glottal stop in Old Mandarin. The Zhongyuan Yinyun, a rime book of 1324, already shows signs of glottal stop disappearing and the modern Mandarin tone system emerging in its place. The precise time at which the loss occurred is unknown though it was likely gone by the time of the Qing dynasty, in the 17th century.

Example

Entering tone in Chinese

Mandarin

The entering tone is extant in Jianghuai Mandarin and Minjiang Sichuanese. Other dialects have lost the entering tone, and syllables that had the tone have been distributed into the four modern tonal categories, depending on their initial consonants.
The Beijing dialect that forms the basis of Standard Mandarin redistributed syllables beginning with originally unvoiced consonants across the four tones in a completely random pattern. For example, the three characters, all pronounced in Middle Chinese, are now pronounced jī jǐ jì, with tones 1, 3 and 4 respectively. The two characters 割／葛, both pronounced, are now pronounced gē and gé/gě respectively, with the character 葛 splitting on semantic grounds.
Similarly, the three characters 胳阁各 are now pronounced gē gé gè. The four characters 鸽蛤颌合 are now pronounced gē gé gé gě.
In those cases, the two sets of characters are significant in that each member of the same set has the same phonetic component, suggesting that the phonetic component of a character has little to do with the tone class that the character is assigned to.
In other situations, however, the opposite appears to be the case. For example, the group of six homophones, all in Middle Chinese and divided into a group of four with one phonetic and a group of two with a different phonetic, splits so that the first group of four is all pronounced fú and the second group of two is pronounced fù. Situations like this may result from the fact that only one of the characters in each group normally occurs in speech with an identifiable tone, and as a result, a "literary pronunciation" of the other characters was constructed based on the phonetic element of that character.
The chart below summarizes the distribution in the different dialects.

Identifying checked tones in Modern Standard Mandarin

There are several conditions that can be used to determine if a character historically had a checked tone in Middle Chinese based on its current reading in Modern Standard Mandarin. However, there are many characters, such as,,, and which do not satisfy any of these conditions at all.

Initial	Final	Tone	Exceptions
Tenuis obstruent: b, d, g, j, zh, z	Non-nasal final	Second tone
Alveolar consonant: d, t, n, l, z, c, s or r	e	Any	,
Velar consonant: g, k, h Retroflex consonant: zh, ch, sh, r	uo	Any	咼果 ,
Bilabial consonant: b, p, m Alveolar non-sibilant consonant: d, t, n, l	ie	Any
Non-labial tenuis obstruent: d, g, z Non-labial fricative: h, s	ei	Any
f	a, o	Any
Alveolar sibilant: z, c, s	a	Any
Any	üe	Any	's variant reading of,

A character with a nasal final in Modern Standard Mandarin will have the checked tone in Middle Chinese.
A character with the sibilant final // in Standard Chinese, i.e. those with initials,, and final, will have the checked tone in Middle Chinese.
A character with the final -uai or -uei in Modern Standard Mandarin will not have the checked tone in Middle Chinese.
A character with a tenuis obstruent initial
Characters that begin with an unaspirated obstruent and end in a nasal final in Mandarin almost never have light level tone. This is a corollary of the first condition in the table above, where characters that begin with an unaspirated obstruent, end in a vowel, and have a light level tone in Mandarin almost always derive from an entering tone. As such, and are not recognised syllables in Standard Chinese.
If a character has a phonetic component that is known to have an entering tone, other characters that have that phonetic component probably have an entering tone. For example, if one already knows that has entering tone, one can conjecture that,,, also have entering tone. However, there are plenty of exceptions, such as and, which lack the entering tone.
Wu

Most varieties of Wu Chinese preserve the entering tone. However, no contemporary Wu varieties preserve the , or distinction, but instead merges them all into a glottal stop. For example, in Shanghainese, the three lexemes,,, historically ending in, and, all end in a glottal stop, and are pronounced .
In some modern Wu varieties such as Wenzhounese, even the glottal stop has disappeared, and the entering tone is preserved as separate tone, with a falling-rising contour, making it unequivocally a phonemic tone in modern linguistics.
The pitch of the entering tones are divided into two registers, depending on the initials:

"dark entering", a high-pitched checked tone, with a voiceless initial.
"light entering", a low-pitched checked tone, with a voiced initial.

Many terms with grammatical functions also undergo sporadic evolution and gain a checked tone. This process can be considered a form of lenition, and is sometimes considered a form of glottalization.
Romanization used is Wugniu. This phenomenon can also be seen in many pronouns, such as Shanghainese and Yuyaonese .

Cantonese

In general, Cantonese preserves the Middle Chinese finals intact, including the differentiation between -p, -t and -k final consonants. Standard Cantonese does not use any glottal stops as final consonants; an exception is the sentence suffix 嘞.
There are a few isolated cases where the final consonant has changed as a result of final dissimilation, but they remain in the checked tone.

Chinese character	Middle Chinese	Standard Cantonese	Hakka	Sino-Korean	Sino-Vietnamese
法	pjop	faat'³	fap	법	pháp
乏	bjop	fat'⁶	fa̍t	핍	phạp

Like most other Chinese variants, Cantonese has changed initial voiced stops, affricates and fricatives of Middle Chinese to their voiceless counterparts. To compensate for losing that difference, Cantonese has split each Middle Chinese tones into two, one for Middle Chinese voiced initial consonants and one for Middle Chinese voiceless initial consonants. In addition, Cantonese has split the dark-entering tone into two, with a higher tone for short vowels and a lower tone for long vowels. As a result, Cantonese now has three entering tones:

Upper dark entering / short dark entering
Lower dark entering / long middle entering
Light entering

Some variants of Yue Chinese, notably including that of Bobai County in Guangxi and Yangjiang in Guangdong, have four entering tones: the lower light tone is also differentiated according to vowel length, short vowels for upper light and long vowels for lower light. Thus in such varieties:

Upper dark entering / short dark entering
Lower dark entering / long middle entering
Upper light entering / short light entering
Lower light entering / long light entering

Chinese character	Middle Chinese	Standard Cantonese	Vowel length in standard Cantonese	Bobai dialect	Sino-Vietnamese
北	pok	bak¹	short		bắc
百	paek	baak³	long		bách
薄	bak	bok⁶	short		bạc
白	baek	baak⁶	long		bạch
竹	tsyowk	zuk¹	short		trúc
捉	tsraewk	zuk³, zuk¹	short		tróc
鐲	dzyowk, draewk	zuk⁶	short		trạc
濁	draewk	zuk⁶	short		trọc