The communicative functions of five signing chimpanzees (Pan troglodytes)

Speech act theory describes units of language as acts which function to change the behavior or beliefs of the partner. Therefore, with every utterance an individual seeks a communicative goal that is the underlying motive for the utterance’s production; this is the utterance’s function. Studies of deaf and hearing human children classify utterances into categories of communicative function. This study classified signing chimpanzees’ utterances into the categories used in human studies. The chimpanzees utilized all seven categories of communicative functions and used them in ways that resembled human children. The chimpanzees’ utterances functioned to answer questions, request objects and actions, describe objects and events, make statements about internal states, accomplish tasks such as initiating games, protest interlocutor behavior, and as conversational devices to maintain and initiate conversation.