Beast Speech is a Non-Combat Skill that is described in game as "Skill in speaking while in the form of an animal or monstrous beast."
Speaking while in one of the Animal Forms will cause random words to be replaced by animal sounds of the same length, so that "Please help me with my quest" might be broadcast to other players as "Moooo help mu with mo quest", if you happen to be a cow at the time.
The higher your level is in beast speech the less likely a word is to be replaced.
Level Up Rewards:Edit
Having people be able to understand you.. duh