Each region on Terrinor has its own language, spoken by all who live there regardless of species. Some specific cultures also have their own private tongues. You can learn other languages by listening to fluent speakers; until you have fully mastered a language, however, you may garble key words or not understand others. You will write in the language you are currently speaking.
See also: accent, say, speak, gobbish, edder, tradespeak, kttik, dark tongue, imperial rowan, low rowan