Modeling the effect of palate shape on the articulatory-acoustics mapping

Abstract

Previous research [Brunner et al. (2009, JASA 125(6), 3936-3949) and Bakst & Lin (ICPhS 2015)] shows that articulatory variability is reduced for people with flatter palates. Brunner et al. (2009) hypothesized that this is because the mapping between articulation and acoustics is more linear for flatter than for more domed palates; in order to maintain similar levels of acoustic consistency, people with flatter palates must be more articulatorily precise than people with more domed palates. A revised version of the Maeda synthesizer was used to model how vocal tract anatomy influences the mapping of articulation onto acoustics, using American English /r/ as a test case. A retroflex-able tongue tip was added to the synthesizer. Two additional palate shapes were also added to the synthesizer, and a script was used to search the articulatory-acoustic space for vocal tract configurations that resulted in a low F3 (the hallmark acoustic cue for /r/) for each palate. Palate shape influences not only the overall sensitivity of the articulatory-acoustic mapping, but also the effect of each individual articulatory parameter on F3.