Portuguese phonology

The phonology of Portuguese varies among dialects, in extreme cases leading to some difficulties in mutual intelligibility. This article on phonology focuses on the pronunciations that are generally regarded as standard. Since Portuguese is a pluricentric language, and differences between European Portuguese, Brazilian Portuguese, and Angolan Portuguese can be considerable, varieties are distinguished whenever necessary.

Consonants

The consonant inventory of Portuguese is fairly conservative. The medieval Galician-Portuguese system of seven sibilants is still distinguished in spelling, but is reduced to the four fricatives by the merger of into and apicoalveolar into either or, except in parts of northern Portugal. These changes are known as deaffrication. Other than this, there have been no other significant changes to the consonant phonemes since Old Portuguese. However, several consonant phonemes have special allophones at syllable boundaries, and a few also undergo allophonic changes at word boundaries.
Phonetic notes

Semivowels contrast with unstressed high vowels in verbal conjugation, as in rio 'I laugh' and riu 'he laughed.' Phonologists debate whether their nature is vocalic or consonantal. In intervocalic position semivowels are ambisyllabic, they are associated to both the previous syllable and the following syllable onset.
In Brazil and Angola, the consonant hereafter denoted as is realized as a nasal palatal approximant, which nasalizes the vowel that precedes it: ninho 'nest'.
is often the pronunciation of a sequence of followed by in a rising diphthong in Brazil, forming a minimal pair between sonha and Sônia ; menina, "girl".
is often the pronunciation of a sequence of followed by in a rising diphthong in Brazil; e.g. limão, "lemon" ; sandália, "sandal".
The consonant is velarized in all positions in European Portuguese, even before front vowels. In Portugal, the unvelarized lateral appears only in non-standard dialects.
The consonant hereafter denoted as has a variety of realizations depending on dialect. In Europe, it is typically a uvular fricative. There is also a realization as a voiceless uvular fricative, and the original pronunciation as an alveolar trill also remains very common in various dialects. A common realization of the word-initial in the Lisbon accent is a voiced uvular fricative trill. In Africa and Asia, the classical alveolar trill is still mostly dominant, due to separate development from European Portuguese. In Brazil, can be velar, uvular, or glottal and may be voiceless unless between voiced sounds; it is usually pronounced as a voiceless velar fricative, a voiceless glottal fricative or voiceless uvular fricative. See also Guttural R in Portuguese. All those variants are transcribed with in this article.
and are normally, as in English. However, a number of dialects in northern Portugal pronounce and as apico-alveolar sibilants which are exactly the same as the ones found in Catalan and Northern European Spanish. Those apico-alveolars sound like duller versions of and, but they are kept apart from which are laminal postalveolar. A small number of northeastern Portugal dialects still retain the medieval distinction between apical and laminal sibilants, a distinction also found in Mirandese and analogous to the distinción of European Spanish.
As phonemes, and occur only in assimilated or unassimilated loanwords, with a tendency for speakers to substitute into fricatives in Portugal. However, in most Brazilian dialects t and d are pronounced as and before,, consonants and at the end of words.
In northern and central Portugal, the voiced stops,, are usually lenited to fricatives,, and respectively, except at the beginning of words, or after nasal vowels; a similar process occurs in Spanish.
In large parts of northern Portugal, e.g. Trás-os-Montes, and also in East Timor and the islands of Flores, and are merged, both pronounced, as in Spanish.
and are realized as and in all positions by a considerable quantity of dialects, especially before and. Because of this, it is mostly agreed upon that the alveolo-palatal fricatives are also valid descriptions of the and phonemes.

Rhotics

The occurrence of the two rhotic phonemes and is mostly predictable by context, with dialectal variations in realization.
The rhotic is predicted to be "hard" in the following circumstances:

Syllable-initially when not following an oral vowel
Following a nasal vowel
Syllable-finally, in most Brazilian and some African dialects

The rhotic is predicted to be "soft" when it occurs in syllable onset clusters or, in some dialects, syllable-finally.
The rhotic phonemes and contrast only between an oral vowel and a vowel, similar to Spanish. In this context, they are spelled "rr" and "r", respectively.
This restricted variation has prompted several authors to postulate a single rhotic phoneme. and see the soft as the unmarked realization and that instances of intervocalic result from gemination and a subsequent deletion rule. Conversely, argue that the hard is the unmarked realization.

Brazilian rhotics

In addition to the phonemic variation between and between vowels, up to four allophones of the "merged" phoneme /R/ are found in other positions:

A "soft" allophone in syllable-onset clusters, as described above;
A default "hard" allophone in most other circumstances;
In some dialects, a special allophone syllable-finally ;
Commonly in all dialects, deletion of the rhotic word-finally.

The default hard allophone is some sort of voiceless fricative in most dialects, e.g.,, although other variants are also found. For example, an alveolar trill is found in certain conservative dialects down São Paulo, of Italian-speaking, Spanish-speaking, Arabic-speaking, or Slavic-speaking influence. A uvular trill is found in areas of German-speaking, French-speaking, and Portuguese-descended influence throughout coastal Brazil down Espírito Santo, most prominently Rio de Janeiro.
The syllable-final allophone shows the greatest variation:

Many dialects use the same voiceless fricative as in the default allophone. This may become voiced before a voiced consonant, esp. in its weaker variants.
The soft occurs for many speakers in Southern Brazil and São Paulo city.
An English-like approximant or vowel occurs elsewhere in São Paulo as well as Mato Grosso do Sul, southern Goiás, central and southern Mato Grosso and bordering regions of Minas Gerais, as well as in the urban areas in the Sinos river valley. This pronunciation is stereotypically associated with the rural "caipira" dialect.

Throughout Brazil, deletion of the word-final rhotic is common, regardless of the "normal" pronunciation of the syllable-final allophone. This pronunciation is particularly common in lower registers, although found in most registers in some areas, e.g., Northeast Brazil, and in the more formal and standard sociolect. It occurs especially in verbs, which always end in R in their infinitive form; in words other than verbs, the deletion is rarer and seems not to occur in monosyllabic non-verb words, such as mar. Evidence of this allophone is often encountered in writing that attempts to approximate the speech of communities with this pronunciation, e.g., the rhymes in the popular poetry of the Northeast and phonetic spellings in Jorge Amado's novels and Gianfrancesco Guarnieri's play Eles não usam black tie.
The soft realization is often maintained across word boundaries in close syntactic contexts.

Consonant phonotactics

Syllables have the maximal structure of CCVVCC. The majority of syllables are open, with CV syllables found to compose 60% of a corpus of Portuguese, followed by CVC and V. Syllables ending in a consonant generally end in one of the single consonants,,, : European Portuguese allows coda, and, and Brazilian Portuguese allows coda and . Syllables ending in two consonants are very rare, and involve a sibilant preceded by another consonant; examples include the first syllables of perspicaz and solstício.
Phonotactic rules concerning onset consonants:

The native Portuguese consonant clusters, where there is not epenthesis, are sequences of a non-sibilant oral consonant followed by the liquids or, and the complex consonants. Some examples: flagrante, complex'o, fixo, latex, qua'tro, guaxinim,
The consonants and occur word-initially only in a few borrowed words and in forms of the clitic pronoun lhe. They are almost always found in the middle of a word between vowels, and are rare before.
The semivowels and do not occur before and respectively.
Regarding Brazilian Portuguese, analyzes the phonetic clusters at the start of words like qual and guardar as separate phonemes, and, rather than as or followed by in phonemic sequence. This is because when or is combined with a different approximant or when is combined with a different initial consonant, the relevant approximant can always be alternatively realized as a full vowel in Brazilian Portuguese: quiabo, guiar, suar. However, this alternation can never apply to the phonetic clusters and : qual and guardar in Brazilian Portuguese are always and, never * or *.

Phonotactic rules concerning coda consonants:

Although nasal consonants do not normally occur at the end of syllables, syllable-final may be present in rare learned words, such as abdómen. In Brazilian varieties, these words have a nasal diphthong.
While the sibilant consonants contrast word-initially and intervocalically, they appear in complementary distribution in the syllable coda. For many dialects, the sibilant is a postalveolar in coda position. In many other dialects of Brazil, the postalveolar variant occurs in some or all cases when directly preceding a consonant, including across word boundaries, but not word-finally. In a number of Brazilian dialects, this "palatalization" is absent entirely. Voicing contrast is also neutralized, with or occurring before voiced consonants and or appearing before voiceless consonants and before a pause. In the vast majority of dialects, however, word-final "s" and "z" are pronounced /z/ before vowels. In European dialects, the postalveolar fricatives are only weakly fricated in the syllable coda.
In most Brazilian dialects, is vocalized to at the end of syllables, but in the dialects of the extreme south, mainly along the frontiers with other countries, it has the full pronunciation or the velarized pronunciation. In some caipira registers, there is a rhotacism of coda to retroflex. In casual BP, unstressed il can be realized as, as in fácil .
For speakers who realize as an alveolar trill, the sequence can coalesce into a voiced alveolar fricative trill.
The semivowels and only contrast in some diphthongs like in pai versus pau. Otherwise they are the non-syllabic allophones of and in unstressed syllables.

Epenthesis

In BP, an epenthetic vowel is sometimes inserted between consonants, to break up consonant clusters that are not native to Portuguese, in learned words and in borrowings. This also happens at the ends of words after consonants that cannot occur word-finally. For example, psicologia may be pronounced ; adverso may be pronounced ; McDonald's may be pronounced. In northern Portugal, an epenthetic may be used instead,,, but in southern Portugal there is often no epenthesis,,. Epenthesis at the end of a word does not normally occur in Portugal.
Epenthetic vowels are traditionally unstressed in BP, but some verbs have alternative pronunciations that display innovative stress on an originally epenthetic vowel: for example, adapto "I adapt" and opto "I opt" can be pronounced in BP either as, or as, .

Consonant elision

There is a variation in the pronunciation of the first consonant of certain clusters, most commonly C or P in cç, ct, pç and pt. These consonants may be variably elided or conserved. For some words, this variation may exist inside a country, sometimes in all of them; for others, the variation is dialectal, with the consonant being always pronounced in one country and always elided in the other. This variation affects 0.5% of the language's vocabulary, or 575 words out of 110,000. In most cases, Brazilians variably conserve the consonant while speakers elsewhere have invariably ceased to pronounce it. The inverse situation is rarer, occurring in words such as fato and contato. Until 2009, this reality could not be apprehended from the spelling: while Brazilians did not write consonants that were no longer pronounced, the spelling of the other countries retained them in many words as silent letters, usually when there was still a vestige of their presence in the pronunciation of the preceding vowel. This could give the false impression that European Portuguese was phonologically more conservative in this aspect, when in fact it was Brazilian Portuguese that retained more consonants in pronunciation.
Unlike its neighbor and relative Spanish, Brazilian Portuguese lacks a tendency to elide any stop, including those that may become a continuant by lenition, but it has a number of allophones to replace someone of them.

Vowels

Portuguese has one of the richest vowel phonologies of all Romance languages, having both oral and nasal vowels, diphthongs, and triphthongs. A phonemic distinction is made between close-mid vowels and the open-mid vowels, as in Catalan, French and Italian, although there is a certain amount of vowel alternation. European Portuguese also has two central vowels, one of which tends to be elided like the e caduc in French.
The central closed vowel only occurs in European Portuguese when e is unstressed, e.g. presidente, as well as in Angola; where unlike Portugal, it only occurs in final syllables, e.g. presidente. However, does not exist in Brazil, e.g. presidente.
In Angola, and merge to, and appears only in final syllables rama. The nasal becomes open.

Vowel classification

In some cases, Portuguese uses vowel height to contrast stressed syllables with unstressed syllables:

In Portugal, unstressed tend to be raised to, whereas remain unchanged. In final syllables, only appear.
In the Southern, Central-West and Southeast regions of Brazil, unstressed are raised to, whereas in Northern and Northeast regions, they remain open. However, stressed remain unchanged throughout the whole territory. In final syllables, only appear.
In Angola, unstressed remain unchanged. In final syllables, only appear.

See [|below] for details. The dialects of Portugal are characterized by reducing vowels to a greater extent than others. Falling diphthongs are composed of a vowel followed by one of the high vowels or ; although rising diphthongs occur in the language as well, they can be interpreted as hiatuses.
European Portuguese possesses quite a wide range of vowel allophones:

All vowels are lowered and retracted before :.
All vowels are raised and advanced before alveolar, palato-alveolar and palatal consonants:. Those are the vowels shown on the chart. The diphthong is an exception to that as it is often pronounced in Lisbon, with a back onset.

Furthermore, Cruz-Ferreira gives voiceless allophones of,, in the unstressed word-final position.
The exact realization of the varies somewhat amongst dialects. In Brazil, the vowel can be as high as in any environment. It is typically closer in stressed syllables before intervocalic nasals than word-finally, reaching as open a position as in the latter case, and open-mid before nasals, where can be nasalized. In European Portuguese, the general situation is similar, except that in some regions the two vowels form minimal pairs in some European dialects. In central European Portuguese this contrast occurs in a limited morphological context, namely in verb conjugation between the first person plural present and past perfect indicative forms of verbs such as pensamos and pensámos. Spahr proposes that it is a kind of crasis rather than phonemic distinction of and. It means that in falamos 'we speak' there is the expected prenasal -raising:, while in falámos 'we spoke' there are phonologically two in crasis: . Close-mid vowels and open-mid vowels contrast only when they are stressed. In unstressed syllables, they occur in complementary distribution. In Brazilian Portuguese, they are raised to close after a stressed syllable, or in some accents and in general casual speech, also before it.
According to Mateus and d'Andrade, in European Portuguese, the stressed only occurs in the following three contexts:

Before a palatal consonant
Before the palatal front glide
Before a nasal consonant

English loanwords containing stressed or are usually associated with pre-nasal as in rush, or are influenced by orthography as in clube, or both, as in surf/surfe.

European Portuguese "e caduc"

European Portuguese possesses a near-close near-back unrounded vowel, transcribed in this article. It occurs in unstressed syllables such as in pegar .

Traditionally, all instances of are pronounced; e.g. verdade, perigo, estado.
In modern European Portuguese, the initial is fronted to ; e.g. energia →.
In traditional EP, was never retracted to. In modern EP, it happens when it is surrounded by, so that ministro, príncipe and artilhar are usually pronounced, and.
When "e" is surrounded by another vowel, it becomes ; e.g. real.
However, when the e caduc is preceded by a semi-vowel, it may be given the unreduced pronunciation of the letter, that is or : poesia, quietude.
Regardless of the underlying phoneme, a phonetic can be elided, affecting syllabification and sometimes even producing a syllabic consonant; e.g. verdade →, perigo →, estado →, energia →, ministro →, príncipe →, artilhar →, caminhar →, pistola → . This can result in complex syllable onsets that are typical of Slavic languages.
Whenever is elided, obstruents in the resulting consonant cluster often agree in voicing, so that the most reduced form of desistiu ' gave up' surfaces as., a phonological sonorant, behaves like an obstruent in this case and can also be devoiced in voiceless clusters, as in reconhecer 'to recognize'.

There are very few minimal pairs for this sound, including pregar vs. pregar as well as jure vs. júri .

Oral diphthongs

Diphthongs are not considered independent phonemes in Portuguese, but knowing them can help with spelling and pronunciation.

Diphthong	Usual spelling	Example	Meaning	Notes and variants
	ai, ái	pai náiade	'father' 'naiad'	In Brazil, it may be realized as before a post-alveolar fricative, making baixo realized as.
	ai	plaina	'jointer'	In several Brazilian dialects; it occurs before nasal consonants and can be nasalised, as in plaina.
	ei, éi, êi	leite anéis contêiner	'milk' 'rings' 'container'	In Greater Lisbon can be centralized to before palatals.; e.g. roupeiro, brenha, texto, vejo, coelho, anéis. Before, it is often a back vowel : etc.
	ei, êi	rei Plêiades	'king' 'Pleiades'	In several vernacular dialects, "ei" may be realized essentially as in unstressed syllables. Words ending on either -eiro or -eira, when ei precedes a palatal sound, or when ei precedes a consonant in general are optionally monophthongized, depending on the speaker and region. However, notice that when ei makes up part of a Greco-Latin loanword, as well as nouns ending on -ei and seis, reino keep their palatal sound . In most stressed syllables, the pronunciation is. There are very few minimal pairs for and, all of which occur in oxytonic words. In Greater Lisbon, however, it is always pronounced.
	ei, éi	geleia papéis	'jelly' 'papers'	It only occurs in -el plurals like anéis. In Greater Lisbon, however, it is always pronounced.
	oi, ôi	dois escôiparo	'two' 'scoiparo'
	oi, ói	heroico destrói	'heroic' 'destroys'	Pronounced as mostly on -oi ending words like herói 'hero', as well as some verbal conjugations.
	ui	fui	'I went'	Usually stressed.
	au, áu	mau áurea	'bad' 'aurea'
	au	saudade trauma	'to miss' 'trauma'	In EP, when unstressed. In several Brazilian dialects; it occurs before nasal consonants and can be nasalised, as in trauma.
	eu, êu	seu terapêutico	'your'/'yours' 'therapeutic'	There are very few minimal pairs for and, all occurring in oxytonic words.
	éu	céu	'sky'	There are very few minimal pairs for and, all occurring in oxytonic words.
	iu	viu	'he saw'	Usually stressed.
	ou	ouro	'gold'	Merges optionally with in most of modern Portuguese dialects, excluding some regions in northern Portugal.

There are also some words with two vowels occurring next to each other like in iate and sábio may be pronounced both as rising diphthongs or hiatus. In these and other cases, other diphthongs, diphthong-hiatus or hiatus-diphthong combinations might exist depending on speaker, such as or even for suo, and in BP or even for fatie.
and are non-syllabic counterparts of the vowels and, respectively. At least in European Portuguese, the diphthongs tend to have more central second elements – note that is also more weakly rounded than the monophthong.

Nasal vowels

Portuguese also has a series of nasalized vowels. analyzes European Portuguese with five monophthongs and five diphthongs, all phonemic:. Nasal diphthongs occur mostly at the end of words, and in a few compounds.
As in French, the nasal consonants represented by the letters ⟨m n⟩ are deleted in coda position, and in that case the preceding vowel becomes phonemically nasal, e.g. in genro . But a nasal consonant subsists when it is followed by a plosive, e.g. in cantar . Vowel nasalization has also been observed non-phonemically as result of coarticulation, before heterosyllabic nasal consonants, e.g. in soma . Hence, there is a difference between phonemic nasal vowels and those that are allophonically nasalized. Additionally, a nasal monophthong written ⟨ã⟩ exists independently of these processes, e.g. in romã . Brazilian Portuguese is seen as being more nasal than European Portuguese due to the presence of these nasalized vowels. Some linguists consider them to be a result of external influences, including the common language spoken at Brazil's coast at time of the European arrival, Tupi.
The and distinction does not exist for nasal vowels; ⟨em om⟩ are pronounced as close-mid. In BP, the vowel is sometimes phonemically raised to when it is nasal, and also in stressed syllables before heterosyllabic nasal consonants : compare for instance dama sã or and dá maçã or . may also be raised slightly in word-final unstressed syllables.
Nasalization and height increase noticeably with time during the production of a single nasal vowel in BP in those cases that are written with nasal consonants ⟨m n⟩, so that may be realized as or. Whenever a nasal vowel is pronounced with a nasal coda the nasalization of the vowel itself is optional.
The following examples exhaustively demonstrate the general situation for BP.romã : : final vowel is "nasal" and nasal approximants may not be pronounced.genro : or or : nasal consonant deleted; preceding vowel is "nasal" and nasal approximants may be pronounced.cem : : nasal approximant must be pronounced.cantar : : nasal consonant remains because of the following plosive; preceding vowel is raised and nasalized non-phonemically. cano : or : first vowel is necessarily raised, and may be nasalized non-phonemically.tomo : or : first vowel may be nasalized non-phonemically.
It follows from these observations that the vowels of BP can be described simply in the following way.

BP has eight monophthongs——whose phonetic realizations may be affected by a nasal archiphoneme. The vowel is typically nasalized, but this is not phonemic.
All eight vowels are differentiated in stressed and unstressed positions. But in word-final unstressed position and not followed by, they reduce to three vowels——in most dialects. In this position, has a free variation and this fatally impairs distinction.
Like the ん of Japanese, the archiphoneme is a nasal archiphoneme of syllabic codas and its actual place of articulation is determined by the following sound:
*=;
*=;
*=;
*
The system of eight monophthongs reduces to five——before and also in stressed syllables before heterosyllabic nasal consonants. The grapheme ⟨a⟩ stands for in these cases.
is not allowed at word-final position because ⟨em⟩ stands for in this case. This is the only case of in coda-position.

With this description, the examples from before are simply. Note that the aforementioned description may only apply to Southern-Southeastern dialects of Brazilian Portuguese. But there is no commonly accepted transcription for Brazilian Portuguese phonology.
Vowel nasalization in some dialects of Brazilian Portuguese is very different from that of French, for example. In French, the nasalization extends uniformly through the entire vowel, whereas in the Southern-Southeastern dialects of Brazilian Portuguese, the nasalization begins almost imperceptibly and then becomes stronger toward the end of the vowel. In this respect it is more similar to the nasalization of Hindi-Urdu. In some cases, the nasal archiphoneme even entails the insertion of a nasal consonant such as, as in the following examples:banco tempo pinta sombra mundo fã falam bem vim bom um mãe pão põe

''muito''

Nasal diphthongs

Most times nasal diphthongs occur at the end of the word. They are:-ãe. It occurs in mãe and in the plural of some words ending in -ão, e.g., cães, pães ; and exceptionally non-finally in cãibra. In Central European Portuguese, it occurs also in all words ending in -em, like tem, bem, mentem, etc.-em. It occurs, both stressed and unstressed, in Brazilian Portuguese and in European Portuguese in word-final syllables ending in -em or -ém, like bem, sem, and além, as well as in verbs ending in -em. In Greater Lisbon, has merged with ; and it occurs duplicated in têm or, which in Brazilian is homophonous with tem.-õe. It occurs:

* in the present indicative of pôr and its derivatives; in the 2nd person singular, in the 3rd person singular, and non-finally in the 3rd person plural.
*in the plural of many words ending in-ão, e.g., limões, anões, espiões, iões, catiões, aniões, eletrões, neutrões, protões, fotões, positrões and the plurals of all words with the suffix -ção, like comunicações, provocações.-uim or -uin Example: pinguim.ui occurs only in the words muito and the uncommon mui. The nasalisation here may be interpreted as allophonic, bleeding over from the previous m.-ão or -am.. Examples: pão, cão, estão, vão, limão, órgão, Estêvão. When in the -am form they are always the 3rd person of the plural of a verb, like estavam, contam, escreveram, partiram.-om. It occurs in word-final syllables ending in -om like bom and som. However, it may be also monophthongized to.

and are nasalized, non-syllabic counterparts of the vowels and, respectively. In European Portuguese, they are normally not fully close, being closer to. As with the oral, the nasal is not only more central but also more weakly rounded than the monophthong. This is not transcribed in this article.

Vowel alternation

The stressed relatively open vowels contrast with the stressed relatively close vowels in several kinds of grammatically meaningful alternation:

Between the base form of a noun or adjective and its inflected forms: ovo, ovos ; novo, nova, novos, novas ;
Between some nouns or adjectives and related verb forms: adj. seco, v. seco ; n. gosto, v. gosto ; n. governo v. governo ;
Between different forms of some verbs: pôde, pode ;
Between some pairs of related words: avô, avó ;
In regular verbs, the stressed vowel is normally low, but high before the nasal consonants,, ;
Some stem-changing verbs alternate stressed high vowels with stressed low vowels in the present tense, according to a regular pattern: cedo, cedes, cede, cedem ; movo, moves, move, movem ; ceda, cedas, ceda, cedam ; mova, movas, mova, movam . ;
In central Portugal, the 1st. person plural of verbs of the 1st. conjugation has the stressed vowel in the present indicative, but in the preterite, cf. pensamos with pensámos. In BP, the stressed vowel is in both, so they are written without accent mark.

There are also pairs of unrelated words that differ in the height of these vowels, such as besta and besta ; mexo and mecho ; molho and molho ; corte and corte ; meta and meta ; and para and para ; forma and forma .
There are several minimal pairs in which a clitic containing the vowel contrasts with a monosyllabic stressed word containing : da vs. dá, mas vs. más, a vs. à, etc. In BP, however, these words may be pronounced with in some environments.

Unstressed vowels

Some isolated vowels tend to change quality in a fairly predictable way when they become unstressed. In the examples below, the stressed syllable of each word is in boldface. The term "final" should be interpreted here as at the end of a word or before word-final -s.
With a few exceptions mentioned in the previous sections, the vowels and occur in complementary distribution when stressed, the latter before nasal consonants followed by a vowel, and the former elsewhere.
In Brazilian Portuguese, the general pattern in the southern and western accents is that the stressed vowels,, neutralize to,,, respectively, in unstressed syllables, as is common in Romance languages. In final unstressed syllables, however, they are raised to,,. In casual BP, unstressed and may be raised to, on any unstressed syllable, as long as it has no coda. However, in the dialects of Northeastern Brazilian, non-final unstressed vowels are often open-mid,,, independent of vowel harmony with surrounding lower vowels.
European Portuguese has taken this process one step further, raising,, to,, in almost all unstressed syllables. The vowels and are also more centralized than their Brazilian counterparts. The three unstressed vowels are reduced and often voiceless or elided in fast speech.
However, Angolan Portuguese has been more conservative, raising,, to,, in unstressed syllables; and to,, in final unstressed syllables. Which makes it almost similar to Brazilian Portuguese.
There are some exceptions to the rules above. For example, occurs instead of unstressed or, word-initially or before another vowel in hiatus. is often deleted entirely word-initially in the combination becoming. Also,, or appear in some unstressed syllables in EP, being marked in the lexicon, like espetáculo ; these occur from deletion of the final consonant in a closed syllable and from crasis. And there is some dialectal variation in the unstressed sounds: the northern and eastern accents of BP have low vowels in unstressed syllables,, instead of the high vowels. However, the Brazilian media tends to prefer the southern pronunciation. In any event, the general paradigm is a useful guide for pronunciation and spelling.
Nasal vowels, vowels that belong to falling diphthongs, and the high vowels and are not affected by this process, nor is the vowel when written as the digraph .

Further notes on the oral vowels

Some words with in EP have in BP. This happens when those vowels are stressed before the nasal consonants,, followed by another vowel, in which case both types may occur in European Portuguese, but Brazilian Portuguese for the most part allows only mid or close-mid vowels. This can affect spelling: cf. EP tónico, BP tônico "tonic".
In most BP, stressed vowels have nasal allophones,,,,,, etc. before one of the nasal consonants,,, followed by another vowel. In São Paulo, Southern Brazil, and EP, nasalization is nearly absent in this environment, other than in compounds such as connosco, comummente.
Most BP speakers also diphthongize stressed vowels in oxytones to,,,,,, etc., before a sibilant coda. For instance, Jesus, faz, dez . This has led to the use of meia instead of seis when making enumerations, to avoid any confusion with três on the telephone.
In Greater Lisbon, is pronounced when it comes before a palatal consonant,, or a palato-alveolar,, followed by another vowel; also, is pronounced.

Sandhi

When two words belonging to the same phrase are pronounced together, or two morphemes are joined in a word, the last sound in the first may be affected by the first sound of the next, either coalescing with it, or becoming shorter, or being deleted. This affects especially the sibilant consonants,,,, and the unstressed final vowels,,.

Consonant sandhi

As was mentioned above, the dialects of Portuguese can be divided into two groups, according to whether syllable-final sibilants are pronounced as postalveolar consonants, or as alveolar,. At the end of words, the default pronunciation for a sibilant is voiceless,, but in connected speech the sibilant is treated as though it were within a word :

If the next word begins with a voiceless consonant, the final sibilant remains voiceless ; bons tempos or .
If the next word begins with a voiced consonant, the final sibilant becomes voiced as well ; bons dias or .
If the next word begins with a vowel, the final sibilant is treated as intervocalic, and pronounced ; bons amigos or .

When two identical sibilants appear in sequence within a word, they reduce to a single consonant. For example, nascer, desço, excesso, exsudar are pronounced with by speakers who use alveolar sibilants at the end of syllables, and disjuntor is pronounced with by speakers who use postalveolars. But if the two sibilants are different they may be pronounced separately, depending on the dialect. Thus, the former speakers will pronounce the last example with, whereas the latter speakers will pronounce the first examples with if they are from Brazil or if from Portugal. This applies also to words that are pronounced together in connected speech:

sibilant +, e.g., as sopas: either ;
sibilant +, e.g., as 'zonas: either ;
sibilant +, e.g., as chaves: always ;
sibilant +, e.g., os g'enes: always.

Vowel sandhi

Normally, only the three vowels, or, and occur in unstressed final position. If the next word begins with a similar vowel, they merge with it in connected speech, producing a single vowel, possibly long. Here, "similar" means that nasalization can be disregarded, and that the two central vowels can be identified with each other. Thus,

→ ; toda a noite or, nessa altura or .
→ ) ; a antiga and à antiga, both pronounced or. The open nasalized appears only in this environment.
→ ; de idade or .
→ ; fila de espera .
→ ; todo o dia or .

If the next word begins with a dissimilar vowel, then and become approximants in Brazilian Portuguese :

+ V → ; durante o curso, mais que um .
+ V → ; todo este tempo do objeto .

In careful speech and in with certain function words, or in some phrase stress conditions, European Portuguese has a similar process:

+ V → ; se a vires, mais que um .
+ V → ; todo este tempo, do objeto .

But in other prosodic conditions, and in relaxed pronunciation, EP simply drops final unstressed and, though this is subject to significant dialectal variation:durante o curso, este inquilino .todo este tempo, disto há muito .
Aside from historical set contractions formed by prepositions plus determiners or pronouns, like à/dà, ao/do, nesse, dele, etc., on one hand and combined clitic pronouns such as mo/ma/mos/mas, and so on, on the other, Portuguese spelling does not reflect vowel sandhi. In poetry, however, an apostrophe may be used to show elision such as in d'água.

Stress

Primary stress may fall on any of the three final syllables of a word, but most commonly on the last two, as antepenultimate stress is relatively less frequent in the language. There is a partial correlation between the position of the stress and the final vowel; for example, the final syllable is usually stressed when it contains a nasal phoneme, a diphthong, or a close vowel—this is especially relevant given the influence of Indigenous languages in Brazil, as indigenous words often have final stress: urubu 'vulture', açaí 'açai', both of which originate from Tupi and have final stress. The orthography of Portuguese takes advantage of this correlation to minimize the number of diacritics, but orthographic rules vary in different regions, and should not be used as a reliable guide to stress, despite the existing correlations found in the grapheme-phoneme conversion of Portuguese data.
As in English, stress in verbs and non-verbs is computed differently. For verbs, stress is deterministic, as different morphemes determine the location of stress in a given word based on tense, mood, person and number. For this reason, the few examples one can find of minimal pairs of lexical stress involve either different verb forms for a given stem, such as ruíram /ʁuˈiɾɐ̃w̃/ 'they collapsed' vs. ruirão /ʁuiˈɾɐ̃w̃/ 'they will collapse', or a noun-verb pair, such as dúvida /ˈduvidɐ/ 'doubt' vs. duvida /duˈvidɐ/ 's/he doubts'. For example, regardless of which verb one considers, stress is always final for the first person singular in the future simple tense : falarei 'I will speak'. For nouns and adjectives, stress is mostly affected by phonological factors such as syllable weight, although morphology also plays a role, as different suffixes may affect the location of stress in a given word. In simple terms, the algorithm for stress in non-verbs is similar to that of English and Latin : stress is final if the final syllable is heavy and penultimate otherwise. A heavy syllable contains a diphthong or a coda consonant. All other patterns are considered to be irregular in most approaches in the literature, even though subregularities have been determined and discussed in recent studies. Finally, syllable weight has also been shown to affect the position of secondary stress in the language, whose location can vary in words with an odd number of pre-tonic syllables. In such words, there's some experimental evidence showing that the presence of a given syllable containing a coda leads to a preference for secondary stress in said syllable.

Prosody

Tone is not lexically significant in Portuguese, but phrase- and sentence-level tones are important. As in most Romance languages, interrogation on yes–no questions is expressed mainly by sharply raising the tone at the end of the sentence. An exception to this is the word oi that is subject to meaning changes: an exclamation tone means 'hi/hello', and in an interrogative tone it means 'I didn't understand'.
As for prosodic domains, the presence of metrical feet in Portuguese has been called into question in a recent study, which argues that no strong evidence exists in the language that supports this particular domain —despite the presence of stress and secondary stress, both of which are typically associated with feet.