iPhone 4s - speaker doesn't work!

you don't say which speaker isn't working. if you are talking about one on the bottom it's a microphone.

There is a microphone and a speaker on the bottom of the phone.

Jailbroken?

Do the basic troubleshooting steps as needed and described in detain in the User Guide, Appendix B:

Restart phone

Reset Phone

Restore in iTunes using a backup

Restore in iTunes as new, without using a backup

If restoring as new doesn't help, there is a hardware failure and you shoud take it to Apple or whoever provides iPhone warranty service in your county.

Hi had same problem today phone would ring with ring tone working but once answered could not hear person and they could not hear me .... Read a few ideas from others on this forum and realised the problem occurs after connections to bottom connection socket .... So used needle to clean out entrance to socket found fluff this probably from inside pocket etc ... Since cleaned out and it wasn't much it's worked fine .... hope this help others

With thousands of inquiries with similar experience reviewed on discussion boards, and after trying most of the 'fixes', I was prepared for my encounter with the nearest genius bar, 210 miles from my home. No acknowledgement of a problem with the OS, but the genius zeroed in on data corruption after performing a diagnostic exam of my iPhone 4S, finding corrupted data and a few error messages. He was able to discuss probable causes with me that made sense and replace my iPhone with a remanufactured one which we were able to activate while in the store, restoring from iCloud. No charge (out of warranty - no extra AppleCare). This has resulted in full return to function which has lasted 48 hours to date. I had been on a trip to Alaska (in March) where I had plugged in headphones, repeatedly switched iPhone on and off, used Airplane mode repeatedly and updated to 6.1.2. The iPhone was not dropped or plunged in water or snow - just subjected to normal use with some 10 degree F weather exposure episodes. In retrospect, I would have liked a printout of the error messages the genius found while performing the diagnostic tests. Apple still rocks for me.

I toggled mine in and out of airplane mode. Fixed it. Give it a try before doing any of the nonsense above this.

What about the nonsense of responding to a question posted over a hear ago, in a long dead thread? Dont'ya think taltr found a solution by now?