IPhone 4: Can't talk to people unless on speakerphone?

I can't talk to someone on my iPhone unless I'm on speakerphone or have headphones plugged in. The weird thing is if I don't have speakerphone on or have headphones plugged in people can still hear me but I just can't anything? ://

voice memos works and i have tried restoring my phone

any suggestions?

I'm not saying your and idiot or anything, but my mum often has this problem, and all you need to do is turn the volume up on the side. The iphone remembers different volume settings for headphones and speaker phone, which might be why you can talk to people only on speaker or headphones.

i know it seems stupid, but it's worth a try