Morphological variation in the adult vocal tract: A modeling study of its potential acoustic impact

In order to fully understand inter-speaker variability in the acoustical and articulatory domains, morphological variability must be considered, as well. Human vocal tracts display substantial morphological differences, all of which have the potential to impact a speaker's acoustic output. The palate and rear pharyngeal wall, in particular, vary widely and have the potential to strongly impact the resonant properties of the vocal tract. To gain a better understanding of this impact, we combine an examination of morphological variation with acoustic modeling experiments. The goal is to show the theoretical acoustic effect of common inter-speaker differences for a set of English vowels. Modeling results indicate that the effect is indeed strong, but also surprisingly complex and context-specific, even when morphology varies in relatively straightforward ways.