To touch on my favourite subject, the Franco-Manitobain-cum-Québecois singer Daniel Lavoie: there's a song of his called "Ça c'est ça" (paroles) that includes these lines:
C'est rien que des mots quand même,
sauf fais-toi-en pas.
I gather that this latter phrase is an informal version of "Ne t'en fais pas" and means "Don't worry about it" in Québecois French.
He pronounces it thus: [sofɛtwezɑ̃pɑ]
I recognize the [e] generally employed for the digraph "oi" in Québecois French, but the [z] caught me off guard.
My assumption: that it's something like the epenthetic "t" in phrases like "Sera-t-il ... ?" (perhaps an emulation of tenses that end in "t", such as "Serait-il ?", or perhaps truly spontaneous).
My questions would therefore be (and feel free to ignore this numbering):
Is that assumption correct?
Is the phenomenon limited to Québecois French? Is it still used? (The song is from 1977.)
Are there any other consonants that perform this role, or just [z]?
Has there been an analysis of the rules in which this [z] surfaces?