Philip Lieberman Department zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA ofCognitive and Linguistic Scienres, Box 1978. Brown zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA UnioersiQ, Prwidtw~, R1029f2. f’.S.A Joy S. Reidenberg Patrick J. Gannon Received 3 July 199 1 Revision received 1 I Februar) 1992 and accepted 25 February 1992 (r-rwords:speerh, Pvolution, physiology, acoustic analysis. zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA The anatomy, physiology, acoustics and perception of speech: essential elements in analysis of the evolution of human speech Inferences on the evolution ofhuman speech based on anatomical data muat take into account its physiology, acoustics and perception. Human sperch is generated by the supralaryngeal vocal tract (SVT) acting as an acoustic filter on noise sources generated by turbulent airflow and quasi-periodic phonation generated by the activity of the larynx. The formant frequencies, which arc major determinants of phonetic quality, are the frequencies at which relative energy maxima will pass through the SVT filter. Neither the articulator) gestures of the tongue nor their acoustic consequences can be fractionattd into oral and pharyngeal cavity components. Moreover, the acoustic cues that specify individual consonants and vowels are “encoded”, i.e., melded together. Formant frequency encoding makes human speech a vehicle for rapid vocal communication. Non-human primates lack the anatomy that enables modern humans to produce sounds that enhance this process, as well as the neural mechanisms necessary for the voluntary control of speech articulation. The specific claims ofDuchin [ 1990) arr discussed. Journal zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFED oJ' Human Evolution / 1992) 23,447-46 7 zyxwvutsrqponmlkjihgfedcbaZYXW Introduction A number zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA of recent studies have debated the evolution of human speech (Arensburg rt al., 1989, 1990; Duchin, 1990; Laitman & Reidenberg, 1988; Laitman et al., 1990, 1991, 1992; Lieberman et at., 1989; Lieberman, 1985, 1989, 199 I ; Marshall, 1989). This issue is complex and involves the interpretation of fossil anatomy, comparative physiology and archaeologi- cal data and accordingly scholars may reach different conclusions. For example, Arensburg and colleagues have reconstructed the entire vocal tract of the Kebara Neanderthal based solely upon measurements of the specimen’s hyoid bone. We disagree with this method and f&l that, based on this method, Arensburg’s conclusion that Kebara had a fully modern tongue and supralaryngeal airway is not convincing. However, despite differences such as this over the interpretation offossil material, most scholars inherently agree on the principles of physiology and the “laws” of physical acoustics that determine the capabilities of the anatomy involved in the production of human speech. While the intellectual capabilities of Neanderthals is rightly open to debate, the basic mechanisms by which speech is produced and the speech producing ability that would follow from particular anatomy is not. More- over, our knowledge concerning the perception of speech has progressed to the point where wr can evaluate the adaptive value of some aspects of the enhanced phonetic ability of anatomically modern zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA Homo sapiens. Unfortunately, the basic facts concerning the acoustics, phyiology and perception of speech are often misunderstood (e.g., Duchin, 1990). This paper is an attempt to clarify these OO4T-“484!92/ I20447 + 2 1 $08.00/O Q 1992 Academic Press Limited