MouthOff™ This is an app with 36 funny illustrations of mouths. You can animate them in time with a sentence and hold your phone in front of your mouth to make it look like it's you talking. Cute.

Trash Mouth Want to chew someone out? This app has a photo of a mouth and 8 funny insults on a soundboard.

Potty Mouth Intl Translator This app has translations of foreign words into English - only "bad"/cuss/swear words!

Harmonica: Just Use Your Lips! This app simulates a harmonica. It comes with a warning to clean your phone first before you put your mouth on it. It actually works pretty well, and gives you a choice of harmonicas.

Anatomy of the Mouth This is a flash card app that helps you learn the parts of the mouth and their function.