Quantifying vocal tract shape variation and its acoustic impact: a geometric morphometric approach
(3 minutes introduction)
|Amelia J. Gully (University of York, UK)|
The shape of the vocal tract varies considerably between individuals. The relationship between detailed variation in vocal tract shape and the acoustics of speech is not yet well understood, despite its potential for increasing understanding in the fields of voice biometrics, forensic speech science, and personalised speech synthesis. One reason that this topic has not yet been extensively explored is that 3D vocal tract shape is difficult to quantify robustly. Geometric morphometrics is a technique developed in evolutionary biology for statistically valid quantification and comparison of anatomical shapes. This study makes use of 3D magnetic resonance imaging data of the vocal tracts of eight individuals, and accompanying audio recordings, combined with geometric morphometric techniques to determine whether the method offers useful information for speech science. The results suggest a linear relationship between the shapes of the vocal tract and output spectra, and there is evidence of possible sexual dimorphism and allometry (a systematic variation of shape with size) in the vocal tract, although due to the limited sample size the results did not reach statistical significance. The results suggest that geometric morphometrics can provide useful information about the vocal tract, and justify further study using this technique.