Best Answer

Aug 24 2015 | 9:33 pm EDT natasftw

Can they hear you in a regular call? Can Siri hear you? If these are no, it's likely your microphone is damaged.

More Answers

Aug 25 2015 | 1:44 am EDT Ledsteplin

Check your mic everywhere else. Does it work?

Aug 25 2015 | 8:10 am EDT Scatabrain

It's a long shot but why not.

Check privacy settings:

Settings -> Privacy -> Microphone

And see if FaceTime is listed and if toggle is turned Off. If so, turn it On.