Well the discussion is about phonics, so I was thinking of how none of the letters in "oiseaux" are pronounced. That was pointed out to me by a French colleague. Although he stopped at "oiseau", strangely. Anyway I thought it was a common joke of sorts.

I guess you could argue that there is an "aah" after the "oo", so the "a" in "-eaux" counts, but the "aah" is not pronounced where the "a" is written in the word.

Btw, I can't make a good French accent on a keyboard but: oo-aah-zoh.