Comparative development of the vocal apparatus in primates: phylogeny of speech

Abstract

The sophisticated feature of human speech allows us to turn much information encoded by language in the brain into sounds and to communicate it with others rapidly and efficiently. Human speech shows highly sophisticated modifications of supralaryngeal vocal tract (SVT) in volume and shape, through voluntary regulation of the vocal apparatuses, which is usually regulated involuntarily in other mammals. Paleoanthropologists have continued to debate the “origin” of language, evaluating distinct morphological features, which are presumed to underlie just human speech, but such continued efforts have no consensus on the age of the origin. On the other hand, recent advances in empirical studies on the development of the SVT anatomy in nonhuman primates endorse the idea that many of the separate biological foundations of speech had evolved independently before the origin of human beings, under different selection pressures unrelated to speech. The efforts have contributed to our better understanding on the mosaic processes of the speech evolution, and could contribute greatly to exploring the long “evolutionary history” of speech.View full abstract