On the evolution of language: A unified view

Abstract

Language can be operationally defined as a communications system that permits the exchange of new, unanticipated information. Different forms of language appear to have been present in earlier stages of hominid evolution. Human language is unique, at the present time, since it makes use of ‘encoded’ speech to achieve a rapid transfer of information. The supralaryngeal vocal tract of modern Homo sapiens is a useful factor in this encoding process which also involves special neural mechanisms. Other factors like cognitive ability and ‘automatization’ are also necessary for language. Those factors are, however, important for many aspects of human and non-human behavior besides language. The evolution of language appears to have been a gradual process that first led to systems that relied on mixed gestural and vocal communication. Some hominids appear to have retained this system until comparatively recent times. Other hominids appear to have placed a greater reliance on vocal communication. Reconstructions of fossil supralaryngeal vocal tracts show that some forms, Australopithecines and ‘classic’ Neanderthal, lacked the supralaryngeal vocal tract that is necessary for the production of fully encoded human speech. Other fossil forms, Steinheim and Es-Skhūl V, had functionally modern vocal tracts. Others, like Broken Hill, represent intermediate forms. The evolution of human language can be viewed as a three stage process that involved (a) increased reliance on vocal communication in activities like hunting, (b) the enhancement of the vocal repertoire with the evolution of the human supralaryngeal vocal tract which produces acoustic signals that are both more distinct and more resistant to articulatory errors, and (c) the evolution of neural mechanisms that made use of the preadapted properties of the supralaryngeal vocal tract for rapid encoded speech communication.