sorry, quote of a quote, and i don't know who originally said, >there is no standard pronounciation

my american M-W10th says the general rule in US is, as piece of food or flesh(a, a fillet of fish, chicken), it usually fill-ay, but when use as noun for bookbinding, architecture, or as band to hold ones hair in place, or as a vt, to debone meat or fish, it is fill et.

while the poll here hasn't been 100% in agreement, it is in close agreement. i fill et a fish, to have fish fill ays, and to hold my hair out of the way during food preperation, i hold it back with a fill et.
(actually, i have never used the word fillet to describe a hair band, or ribbons woven into braids, but i knew the word, and would have read it aloud as fill et.