Back to basics: I was certain the pronunciation of えい (like in せんせい) was "ee" (except in few cases like in スペイン), I've read that everywhere.
But in one of the few French reference books for learning Japanese, they say it's pronounced "e-i" like the English words "say", "may", "day".
So I was wondering if it is a HUGE mistake of that book, or if it's more subtle than that?
And maybe the same happens with おう?
Thanks.