I can listen to and talk on the phone regularly, but not through the handsfree Speaker. I can listen to music with earphones, but not through the speaker. Also, when a call comes in I can not hear it ring?
Welcome to Android Central! It sounds like the main speaker has failed. Does this persist after a reboot? You could try a factory reset as well, but I doubt that would fix it (and it'd be a hassle as well). You may just have to contact Samsung for repair. Is the phone still under warranty?