The accent of the south, shaped by Occitan underneath it. The nasal vowels are not fully nasal: the mouth closes on an ŋ at the end. The schwa that Paris deletes is pronounced — 'petite' has three syllables — and the mid vowels have no open/closed contrast, so 'rose' has the vowel of 'bonne'. The melody swings.
Where: Marseille, Provence and the south
The way in: Give every e a syllable and close every nasal vowel on ng: 'un bon pain' as œŋ bɔŋ pɛŋ.
Try a word
Anything the spelling engine can transcribe, the accent can move. Slow it down to hear the shape.
The famous sing-song: pitch swings up and down inside the phrase, the final syllable is lengthened, and the schwa that Paris drops gets a full beat — 'une petite maison' has seven syllables here and five in Paris.
What moves, one rule at a time
In the order the mouth applies them. Every before-and-after is playable — click the IPA. The pattern is the rule as the engine runs it, for the curious.
Vowels
The nasal of 'vin' ends in a consonant
ɛ̃ → ɛŋ
How: Say a plain 'è' and close on the ng of 'sing'.
Southern French keeps the nasal consonant that the north absorbed into the vowel in the Middle Ages. The vowel is only lightly nasal; the ŋ carries the rest.
Word
Reference
Accent
pain
vin
bien
…and so does the nasal of 'blanc'
ɑ̃ → ɑŋ
Word
Reference
Accent
blanc
dans
enfant
…and the nasal of 'bon'
ɔ̃ → ɔŋ
Word
Reference
Accent
bon
maison
…and the fourth nasal, which the south still has
œ̃ → œŋ
Marseille never merged brun with brin. Four nasals, all with a consonant on the end.
Word
Reference
Accent
brun
un
The closed o opens
o → ɔ
How: The o of 'bonne' everywhere — jaw open, lips loosely rounded.
The south has one o, and it is the open one. 'Côte' and 'cote' are the same word.
Word
Reference
Accent
rose
beau
chose
The closed eu opens
ø → œ
How: The vowel of 'peur' everywhere.
Word
Reference
Accent
peu
deux
heureux
The closed é opens
e(?![̃]) → ɛ
One e-sound rather than two — the same collapse as the o's.