A Less Complex Larynx Lead Way To Human Speech

Oral communication may have been aided by the evolutionary loss of a thin vocal membrane in the larynx

Compared to other primates, humans have some distinctive physical characteristics. In particular are our vocal tracts as well as the brain power which have allowed our ability to talk. A new study in Science ¹was published online yesterday which suggests a rather counterintuitively notion — the evolution of sophisticated speech may have taken place throughout the course of a human larynx's structural simplicity.

The authors write that the absence of a laryngeal membrane may have helped stabilize vocalization in early humans, enabling considerable information transmission through spoken language, based on comparisons among modern primates, tests, and mathematical modeling.

Vocal anatomy in humans (B) and chimpanzees (C). A frontal MRI scan (left) and drawing (middle) show the region corresponding to an excised larynx at the level of the dash line (right). The vocal membrane (vm) and the sulcus (s) separating the membrane from the vocal fold (vf) in chimpanzees is absent in humans.Nishimura et al., Science 377:760 (2022)

This is a hard suggestion to make, because unline bipedalism, and brain size, languagte isn’t in the fossil record. So, their method for examining the evolution of language is to compare the anatomy of the larynx of nonhuman primates to that of humans.