Communication occurs when signals carry information-bearing messages between a source (or sender) and a destination (or receiver). Although all species communicate, human communication is notable for its precision and flexibility, a consequence of the uniquely human ability to use language. Language endows human communication system with the properties of semanticity, generativity, and displacement, allowing people to formulate an unlimited number of meaningful novel messages that are not tied to the immediate present. At a fundamental level verbal messages convey meanings the speaker has encoded into the words of an utterance, but a listener who has understood the utterance has gone beyond the literal meaning of the words and grasped the particular sense in which the speaker intended them to be understood. In order to do so, communicators must make their coparticipants' perspectives part of the process of formulating and interpreting messages. Thus any communicative exchange is implicitly a joint or collective activity in which meaning emerges from the participants' collaborative efforts.