Why can't I hear the speaker?

Yes there is. You have two separate speaker on your iphone. One is the iphone speaker buzzer which is connect to your antenna. The other speaker is connected to your sync flex cable inside your phone. If your phone still syncs and you don't hear any sound from BOTH of you speakers, you need to replace that entire part. But if you just have one speaker working, you can open it and figure exactly what wrong. the speaker on the right side is connected to the sync cable. the speaker on the left side is connected to the speaker/buzzer part. If you are not handy and you want it simply for you, just purchase the entire part. If you can not find the item on this website, you can find it on ebay. the entire piece will cost you about 25 USD. hopefully this will help you out.