Different palates may have shaped vowel evolution

The shape of the human palate may influence small, systematic speech patterns across different language groups, reports a study published this week in Nature Human Behaviour.

Languages differ not only in grammar and words, but also in speech sounds. Previous research has focused on the cultural and environmental influence on the evolution of language. Any variation in the anatomy of vocal tracts has been assumed to have had little influence on linguistic diversity.

Dan Dediu and colleagues examined how the shape of the human palate influences the pronunciation of five vowel sounds heard across different language families. They used computer models based on 107 MRI scans of human participants representing four broad ethnolinguistic groups: European and North American of European descent, North Indian, South Indian, and Chinese. The authors found that different hard palate shapes in all groups resulted in subtle differences in the acoustics and articulation of all five vowels. However, they show that these individual-level speech idiosyncrasies may have been further amplified when passed down through generations.

The authors conclude that further research is needed to fully understand the role that the anatomy of the vocal tract plays in the evolution of language.