2018.01.17 Prof. Kong Jiangping

Department of Chinese Language and Literature

Peking University

A Study on the Evolution of Voval Tract from Chimpanzees to Humans

As is well known, vowels [a, i, u] are regarded as the basic vowels in human speech. Chimpanzee, on the other hand, can only produce sounds reminiscent of [a] and [u] because of their small back cavity and the specific structure of their tongue muscles, which make it impossible for them to form the vocal-track shapes as observed in human. The differentiation of chimpanzee and modern human dates back to 5 million years ago. Since tongue muscles and larynx cannot be fossilized, it is difficult to reconstruct vocal tracts simply based on the fossils of ancient homos.

Kong’s team has established the physiological models of chimpanzee and modernhuman based on 3D MRI data, which include the parameters of front cavity length,back cavity length, and similarity of vocal tract shapes. Through the vocal tractsimulation from chimpanzee to modern human, about fifty thousand 3D vocal tracts
are reconstructed, and sounds produced in the vocal tracts have been synthesized. By conducting speech sound perception tests, the team explores the time vowels couldhave emerged. Further research will deepen our understanding of the evolution of speech organs, as well as the origin of human language.