The contribution of speech perception for the evolution of the capacity for phonological systems in homo sapiens

The reconstruction of the evolution of the capacity for phonological systems in homo sapiens should not be restricted to the anatomy of the vocal tract; perception and how it interacts with the vocal tract's potential for production need to be included. In the past, the anatomical aspects have been in the forefront, due, notably, to Lieberman's comparative research on human neonates and adults, hominid fossils, and apes (e.g. see Liebermann 1999 for a review). In this paper the focus is on the impact of the auditory system on the evolutionary issue. It is argued that the structure and the functioning of the auditory system as required for natural human languages to function the way they do, antidates the evolution of the vocal tract as required for speech by quite a margin. The data to be considered include speech perception by human neonates, pre-speaking infants, children and adults, as well as non-human animals. The argument is focussed on distinctive features, their typology, and the ability of human beings to categorize the sound wave into segments. It appears that categorical perception constitutes the auditory basis for the phoneme and that the distinctive features are based on the heightened sensitivities of the auditory system. These sensitivities restrict the universal set of sound contrasts that are used for phonemic purposes, and they constitute the biological basis for the typology of the distinctive features.

The paper builds on suggestions repeatedly made by Kuhl that those sound contrasts that are utilized for phonemic purposes in the natural human languages are based on the heightened auditory sensitivities as evidenced by human neonates/infants and non-human mammalian species such as rhesus monkeys and chinchillas (e.g. Kuhl/Miller 1978, Kuhl/Padden 1982, 1983, Kuhl 1981, 1987, 1993). This original claim requires some modifications. Recent evidence on birds indicates that the phenomenon is not restricted to mammals. In addition, a recent study on monkeys shows that the close parallels between humans and the non-human species may apply only to some acoustic dimensions. In addition, the implications for some basic issues in linguistics such as language typology, language acquisition and learnability, as well as innateness need to be developed more fully.

Paper presented at the Conference on the Evolution of Language. Paris, 3.-6.4.2000.