This language differentiates front-rounded from back-rounded vowels, as in vu, "seen" & vous, "you"
Thus, in 
French, there are three front, rounded vowels which are similar to, but not quite 
...... back/front and rounded/unrounded distinctions in vowels can be seen in the 
...... '(they) go' [vy] 'saw' [vu] 'you' (plural) 1 s According to the phonemic principle,
... [DOC] [TLE] The Sounds of English and French.