1. A method of adjusting a voice prompt of a system based upon a state of a user of the system, the method comprising: receiving an utterance of the user; obtaining utterance parameters from the utterance, the utterance parameters indicating the state of the user; determining the state of the user based upon the utterance parameters; and adjusting the voice prompt by adjusting at least one of a tone of voice of the voice prompt, a content of the voice prompt, a prosody of the voice prompt, and a gender of the voice prompt based upon the determined state of the user.