Below is an abstract consonant chart that covers multiple dialects. Where symbols for consonants occur in pairs, the left represents a voiceless consonant and the right represents a voiced consonant.
Notes
The phoneme /ʃ/ is mostly found in Southern Occitan (written ⟨(i)sh⟩ in Gascon, ⟨ch⟩ in Provençal, and ⟨(i)ss⟩ in Languedocien).
The distinction between /v/ ⟨v⟩ and /b/ ⟨b⟩ is general in Provençal, Vivaro-Alpine, Auvergnat and Limousin. However, in Languedocien and Gascon, the phonemes /b/ and /v/ are neutralized as /b/ (thus /v/ has disappeared).
In Languedocien:
the phonemes /b, d, ɡ/ indicate three kinds of sounds, depending on what surrounds them:
a voiced plosive sound [b, d, ɡ] by default
devoiced to [p, t, k] phrase-finally or before a voiceless sound
a voiced fricative [β, ð, ɣ] when both preceded and followed by voiced continuants (i.e., vowels or [r, l, z]) within the same phrase.
the phonemes /ts/ and /dz/ and the sequences /p+s/, /k+s/ are neutralized as /ts/ (thus /dz/, /p+s/ and /k+s/ have disappeared).
In Auvergnat and Limousin, and locally in other dialects,
the phonemes /ts/ and /tʃ/ are neutralized as /ts/ (thus /tʃ/ has disappeared).
the phonemes /dz/ and /dʒ/ are neutralized as /dz/ (thus /dʒ/ has disappeared).
In Auvergnat, most of the consonants, except /r/, can have a palatalized sound before i and u. Consequently, the consonant phonemes have two kinds of sounds, one being not palatal (by default) and the other being palatal (before i and u): /p/ → [p, pj]; /b/ → [b, bj]; /t/ → [t, tj]; /d/ → [d, dj]; /k/ → [k, kj]; /ɡ/ → [ɡ, ɡj]; /f/ → [f, fj]; /v/ → [v, vj]; /s/ → [s, ʃ]; /z/ → [z, ʒ]; /ts/ → [ts, tʃ]; /dz/ → [dz, dʒ]; /m/ → [m, mj]; /n/ → [n, nj]; /l/ → [l, lj].
In one part (and only one part) of Limousin, a transphonologization has occurred:
The old phonemes /ts/, /dz/ have now become /s/, /z/.
The old phonemes /s/, /z/ have now become /ʃ/, /ʒ/.
In the Provençal in general, and partially in other dialects, the phonemes /j/ and /ʎ/ are neutralized as /j/ (thus /ʎ/ has disappeared).
The original rhotic consonants, /ɾ/ (tapped) and /r/ (trilled), have shown important evolutions:
In Provençal and partially in other dialects, there is now an opposition between /ɾ/ (tapped) and /ʀ/ (uvular) (whereas /r/ has disappeared). This feature is shared with Portuguese. In the cases when the opposition is impossible between the two phonemes, the default realization is /ʀ/ (it was /r/ in the original pattern).
In most of Limousin, Auvergne, Vivarais and Niçard, the phonemes /ɾ/ and /r/ are neutralized as /r/ (or even /ʀ/).
Gascon shares some traits with Languedocien:
The phonemes /b, d, ɡ/ have the same realization as described above for Languedocien.
The phonemes /b/ and /v/ of the general pattern are neutralized as /b/. It seems possible, however, that the phoneme /v/ never existed in Gascon.
Gascon and Southern Languedocien do not have the semivowel /ɥ/ (Gascon has /ɥ/, SL has /β/) and have the same distribution for the phonemes /dʒ/ ⟨tg, tj⟩ and /ʒ/ ⟨j, g⟩.
In one part of Gascon, the palatal affricates /tʃ/ /dʒ/ become plosive palatal consonants: /c/, /ɟ/.
Note:
The grapheme ⟨a⟩, when in final position and after the word's stress, is pronounced /ɔ/ in general (locally: /a/, /ə/).
The grapheme ⟨á⟩ is pronounced /ɔ/ in general (locally: /e/, /ɛ/).
In an unstressed position, some vowels cannot be realized and become more closed vowels:
The stressed vowel /ɛ/ ⟨è⟩ becomes the unstressed vowel /e/ ⟨e⟩. For instance (stress underlined): tèrra /ˈtɛrrɔ/ → terrassa /teˈrrasɔ/.
The stressed vowel /ɔ/ ⟨ò⟩ becomes the unstressed vowel /u/ ⟨o⟩. For instance (stress underlined): còde /ˈkɔde/ → codificar /kudifiˈka/.
In some local dialects, especially in the Languedocien variety of Guyenne, the stressed vowel /a/ ⟨a⟩ becomes the unstressed vowel /ɔ/ ⟨a⟩. For instance (stress underlined): bala /ˈbalɔ/ → balon /bɔˈlu/.
Also in Guyenne, the vowel ⟨a⟩, when stressed, is pronounced /ɔ/ when followed by a nasal consonant such as /n, m, ɲ/ ⟨n, m, nh⟩ or a final ⟨n⟩ that is silent: montanha, pan /munˈtɔɲɔ, ˈpɔ/ (instead of /munˈtaɲɔ, ˈpa/).
In Limousin, Auvernhat, Vivaro-Alpine and in most of Provençal (though not in Niçard), the stressed diphthong /aw/ ⟨au⟩ becomes the unstressed diphthong /ɔw/ ⟨au⟩. For instance (stress underlined): sauta /ˈsawtɔ/ → sautar /sɔwˈta/.
In Limousin, Auvernhat, Vivaro-Alpine and in most of Provençal (though not in Niçard), the stressed diphthong /aj/ ⟨ai⟩ becomes the unstressed diphthong /ej/ ⟨ai⟩. For instance (stress underlined): laissa /ˈlajsɔ/ → laissar /lejˈsa/.
One typical characteristic of Auvergnat (also a feature of some neighbouring dialects of Vivaro-Alpine) is the transformation of the following phonemes:
The old phoneme /ɛ/ has become /e/.
The old phoneme /e/ has become /ə/ or /ɪ/.
In an unstressed position, some vowels cannot be realized and become more closed vowels:
The stressed vowel /e/ ⟨è⟩ becomes the unstressed vowel /ə (ɪ)/ ⟨e⟩. For instance (stress underlined): tèrra /ˈterɔ/ → terrassa /təˈrasɔ/.
The stressed vowel /ɔ/ ⟨ò⟩ becomes the unstressed vowel /u/ ⟨o⟩. For instance (stress underlined): còde /ˈkɔdə/ → codificar /kudifiˈka/.
In the northern part of Auvergne, the stressed vowel /a/ ⟨a⟩ (unrounded) becomes the unstressed vowel /ɒ/ ⟨a⟩ (rounded). For instance (stress underlined): bala /ˈbalɔ/ → balon /bɒˈlu/.
The stressed diphthong /aw/ ⟨au⟩ becomes the unstressed diphthong /ɔw (u, œ)/ ⟨au⟩. For instance (stress underlined): sauta /ˈsawtɔ/ → sautar /sɔwˈta/.
The stressed diphthong /aj/ ⟨ai⟩ becomes the unstressed diphthong /ej (i)/ ⟨ai⟩. For instance (stress underlined): laissa /ˈlajsɔ/ → laissar /lejˈsa/.
A strong characteristic of Limousin (also a feature of some neighbouring dialects of Vivaro-Alpine) is the neutralization of the phonemes /e/ and /ɛ/ in one single phoneme /e/, that can have various degrees of opening.
In words of popular formation, the sequences ⟨as, es, is, òs, os, us, ues⟩ [as, es, is, ɔs, us, ys, œs], when at the end of a syllable, first became [ah, eh, ih, ɔh, uh, yh, œh] and have now become long vowels, [aː, (ej), iː, ɔː, uː, yː, œː], which tends to create new phonemes with a relevant opposition between short vowels and long vowels. The same phenomenon exists in one part of Vivarais, and also occurred in the transition from Old to Middle French.
In an unstressed position, some vowels cannot be realized and become more closed vowels:
The stressed vowel /ɔ/ ⟨ò⟩ becomes the unstressed vowel /u/ ⟨o⟩. For instance (stress underlined): còde /ˈkɔde/ → codificar /kudifiˈka/.
The stressed vowel /a/ ⟨a⟩ (unrounded) becomes the unstressed vowel /ɒ/ ⟨a⟩ (rounded). For instance (stress underlined): bala /ˈbalɔ/ → balon /bɒˈlu/.
The stressed diphthong /aw/ ⟨au⟩ becomes the unstressed diphthong /ɔw/ ⟨au⟩. For instance (stress underlined): sauta /ˈsawtɔ/ → sautar /sɔwˈta/.
The stressed diphthong /aj/ ⟨ai⟩ becomes the unstressed diphthong /ej/ ⟨ai⟩. For instance (stress underlined): laissa /ˈlajsɔ/ → laissar /lejˈsa/.
In Limousin and Auvergnat, final consonants, except for ⟨nh⟩ and ⟨m⟩, are generally muted when not directly followed by a word with a vocalic initial: filh [fi], potz [pu], fach [fa], limon [liˈmu] but estelum [ejteˈlun], estanh [ejˈtan], un fach ancian [yn fats ɔnˈsja].
In Limousin and Auvergnat, when a diphthong starts in ⟨o⟩ or ⟨u⟩, it is always a rising diphthong: boisson [bwiˈsu] (Auvergnat) and [bwejˈsu] (Limousin) versus [bujˈsu] (Languedocien) or [bujˈsun] (Provençal).
In all dialects but Languedocien, final ⟨l⟩ is heavily velarized ("dark l") and therefore usually spelled ⟨u⟩: especial [espeˈsjaɫ] / especiau [espeˈsjaw] but especiala [espeˈsjalɔ] in the feminine (except in Gascon where it stays as especiau).
Word stress has limited mobility. It can only fall on:
the last syllable (oxytones or mots aguts 'acute words')
the penultimate syllable (paroxytones or mots plans 'plain words').
However, in Niçard, and less commonly in the Cisaupenc dialect of the Occitan Valleys, the stress can also fall on the antepenultimate (third from last) syllable (proparoxytones or mots esdrúchols 'slip words'). These proparoxytones are equivalent to paroxytones in all other dialects. For instance (stress underlined):
As a Romance language, Occitan developed from Vulgar Latin. Old Occitan (around the eighth through the fourteenth centuries) had a similar pronunciation to present-day Occitan; the major differences were:
Before the 13th century, ⟨c⟩ had softened before front vowels to [t͡s], not yet to [s].
In the early Middle Ages, ⟨z⟩ between vowels represented the affricate [d͡z], not yet /z/.
In early Old Occitan, ⟨z⟩ represented [t͡s] in final position.
In the late Middle Ages, the letter ⟨a⟩ went from [a] to [ɑ] in unaccented position and in stressed syllables followed by a nasal consonant.
When not part of a diphthong, the vowel spelled ⟨o⟩ was probably pronounced as [ʊ], not yet [u].
Between vowels, the letter ⟨i⟩ or ⟨j⟩ represented, for most speech in Occitania, [j]. However, this could become [ʒ], especially down south: it later became [d͡ʒ], which, in turn, would locally depalatalize to [d͡z] in Middle Occitan.
In words where /ɾ/ was preceded by a diphthong whose second element was [j], it was sometimes palatalized to [rʲ].
In earlier times, some dialects used [ç] instead of the more common [ʃ]: despite their similarity, this often led to contrasting spellings (⟨laishar⟩ or ⟨laischar⟩ [lajˈʃaɾ] vs. ⟨laichar⟩ [lajˈçaɾ]; ⟨fois⟩ or ⟨foish⟩ [fʊjʃ] vs. ⟨foih⟩ [fʊiç]) before it became [s] commonly across the language (⟨laissar⟩ [lajˈsaɾ], ⟨Fois⟩ [fujs]).
In the pre-literary period of early Old Occitan /u/ had not been fronted to [y], although strong doubts exist as to when the change actually happened.
When between vowels, /d/ lenited to [ð], though this is still true for only Gascon and Languedocien dialects; elsewhere, it eventually turned to [z] or was deleted.
In Gascon, there was one voiced labial phoneme that was [b] in the beginning of a word and [β] between vowels. This still happens today and has spread to the neighbouring Languedocien dialect.
The phoneme ⟨lh⟩ was exclusively pronounced [ʎ] (it is now [j] in intervocalic or final position in some dialects).
