how I get back speaker function how I get back speaker function iPhone 4S

yesterday the speaker gradually quit working.  some crackles, a sound or two and then nothing.  Now there is no sound from the speaker.  I tried everything.  The headphone jack is working properly, because when you remove headphones the "headphones" sign in the volume graphic disappears.  The phone knows there is nothing in the jack and is therefore not attempting to keep sending audio through headphones. 

It is simply that the speaker no longer works.  The earpiece does, telephone calls are no problem.  and headphones work fine, including the miked ones for making phone calls.  But I cannot hear incoming calls ring, and cannot hear alarms go off, etc.  There is absolutely NO speaker function with any app.

So... headphones work, phone earpiece works, but speaker does not work on any app.

No, mute is not on.

I reset the phone but am not willing to do a full restore unless I know it's worth the effort.  This phone is only a few weeks old.

help!