1. A method for addressee detection, comprising: receiving an utterance; extracting prosodic features directly from a spoken signal corresponding to the utterance; determining patterns of the prosodic features that characterize a speaking style of the utterance as either a human-computer (H-C) or a human-human (H-H) style, indicating whether speech is directed to a computer or another human; characterizing a degree to which a new utterance conforms to the H-C or H-H styles; and using the new utterance according to the characterization of the speaking style.