Investigating the acoustic effect of the descended larynx with articulatory models

A strongly simplified articulatory model, as well as three more realistic models are investigated for the effect of larynx height on the extent of vowel signaling space. The models explore a larger range of larynx positions than previous models, and the use of the convex hull for measuring articulatory abilities is introduced. A short study of human data is also reported. It is found in all cases that a vocal tract with a vertical section that is approximately equally long or slightly shorter than the horizontal section performs best. This corresponds most closely to the anatomy of the female vocal tract. The findings are discussed in light of hypotheses regarding the evolutionary development of the vocal tract.

Research Highlights
► Computer models indicate that the female vocal tract is optimal for speech.
► Measurements confirm children and women have a larger vowel space than adult men.
► Human female vocal tract evolved for speech.
► Human male vocal tract also evolved to exaggerate size.