The recent origin of human speech

Studies of human development and swallowing show that a supralaryngeal vocal tract (SVT) capable of producing quantal vowels involves (1) facial restructuring yielding a short oral cavity; (2) a tongue that moves down into the pharynx carrying the larynx down with it; and (3) a long neck. The skeletal features of hominid fossils suggest the absence of fully human speech anatomy until 100<th>000 years ago. With long faces and short necks, Neanderthals and early anatomically modern humans could not have possessed SVTs capable of swallowing and of producing fully human speech. Probable [i] SVT shapes were computer‐modeled from perturbations of vocal‐tract area functions obtained from MRIs of adult humans. When normalized to the length of an adult human SVT, F1/F2 patterns fall outside of the range of Peterson and Barney’s [‘‘Control methods used in a study of the vowels,’’ J. Acoust. Soc. Am. 30, 739–742 (1952)] data used by Lieberman and Crelin, ‘‘On the speech of Neanderthal man,’’ Linquistic Inquiry 2, 203–222 (1971) to assess Neanderthal speech), but at the extreme range for [i] as measured by Hillenbrand et al. [‘‘Acoustic characteristics of American‐English vowels,’’ J. Acoust. Soc. Am. 97, 3099–3111 (1995)]. In neither case are the high‐frequency spectra characteristic of human quantal [i]’s. F1/F2 patterns for unnormalized SVTs fall outside the human range for both plots.