“you not” (an incomplete, ungrammatical French sequence when used on its own)
Why aren't you growing?
Pourquoi n'abandonnes-tu pas ?
Why don't you give up?
Tu as peur, alors fuis pourquoi ne ramènes tu pas tes potes.
You're scared, so run away, why don't you bring your friends?
— Avatar (2009)
Pourquoi ne leurs mets-tu pas ton poing dans la figure ?
Why don't you just punch them in the face?
— L'Histoire sans fin (1984)
Why aren't you smiling?
Why don't you try?