Communication in animals

The paper deals with the antecedents of human speech in animals, more precisely with the problems of continuity versus discontinuity in communication between the different species of vertebrates. It puts emphasis on higher classes of mammals, namely monkeys and apes. Three ancient structures and mechanisms are listed which may have a role as forerunners of the development of human speech: (1) the activity of the mimic muscles of the cheeks and of the jaws, (2) the evolution of sound-producing specialized membranes in the laryngeal respiratory passages, and (3) the development of hemispheric asymmetries of the brain, which culminated in the emergence of the specific speech areas of the dominant hemisphere in humans. The history of the research of animal language cannot avoid the survey of the fascinating trials made on anthropoid apes. The paper briefly summarizes the four approaches (American Sign Language, plastic tokens, keyboard systems and mimics) with the conclusion that continuity can be demonstrated in brain lateralization and in cognitive abilities, but a marked discontinuity between animal communication and human speech is evident.