A comment by marie-lucie in this thread (which has now reached the hundred-comment mark thanks to the usual digressions, in this case involving edibles) is so interesting I thought I’d give it its own post:
At a time when I was required to read 19th-century French novels, I was struck by a number of occasions in which a young man from the provincial bourgeoisie, sent to Paris as a student but preferring to write verse, got involved with a working-class girl who embarrassed him by pronouncing poète as pouâte, that is, just as poêle is pronounced as if it were written pouâle. I suspect that the girls in question were coming from the (then) rural belt around Paris which preserved the older pronunciation of written oi (as in moi or mois) as [we] while Parisians and most educated people had long switched to [wa], and they made the equation rural [ouè] = Parisian [ouâ], and therefore interpreted the vowel sequence in poète as a forgotten instance of rurality to be avoided in more sophisticated company. Similarly my father’s grandmother, coming from a village South of Paris, pronounced the word fouet ‘whip’ as [fwa] (I never heard her talk about poets).
This must be a common phenomenon; I’m reminded of the confusion between final [i] and [ǝ] in some American dialects (e.g., Missouri vs. “Missoura”), not to mention the recent post about New Zealand [r]. Anybody know of examples in other languages of people trying to avoid a shibboleth and getting it wrong?