speaker phone speakers not working

This is not an earbud issue. I have never plugged mine in. One day I was using the Speaker option and noticed that the sound was scratchy. The next day the phone did not ring it only vibrated. I have a very quite ringtone plus vibrate for incoming calls. The ring sound comes out of the speakers as well as the voice so right now all I have is the vibrate option. Listening out of the speaker by the ear works great. My ringer and speaker are at maximum volume. I have not gotten the phone wet, but I do live in Houston, Texas which has high humidity. Is there something I can do to fix this. I can take the phone apart, but would like to know what I am to do when it is open.

Thank you,

Nicole