When some native speakers pronounce “matin”, which is listed in most dictionaries as [ma.tɛ̃], the nasalized vowel is substantially more back and open than ɛ. This seems much more common than not in Switzerland and in many parts of France. The Wikipedia comments that this sound is [æ̃] in some dialects, but to me, it seems farther back: the characteristics of the two vowels in “matin” are identical except that the second vowel is nasalized (or, if anything, the nasal vowel is farther back than the oral vowel).
(However, in other parts of France I have heard [ma.tɛ̃] pronounced as given in the dictionary.)
My questions are:
Is my analysis of this vowel as being much farther back than the dictionary suggests correct? Do French speakers perceive that this is a significant difference in pronunciation? Which pronunciation would you recommend that a French learner adapt?