Figure 3

The Homo species supralaryngeal tract. The Homo species supralaryngeal tract (right) is characterize by horizontal portion (i.e., mouth and oropharynx) forming a right angle of approximately equal lengths of 1:1 proportion with a vertical segment extending down from the palate to the vocal cords. In comparison, the chimpanzee (left) has a hyoid bone and larynx positioned at or near the base of the mandible; and, the tongue is long and mostly restricted to the oral cavity, resulting in a disproportionate supralaryngeal vocal tract. Human ancestors such as Homo erectus and Neanderthal chronospecies possessed supralaryngeal vocal tracts intermediate in shape between those of chimpanzees and humans. (Adapted from [108]).