Effect of years of voice training on chest and head register tongue shape variability

The transition between head and chest registers in operatic singing has been linked to adjustments in the larynx [Henrich, 2006, LPV 31], vocal tract length [Tokuda et al., 2010, JASA 127], and resonance frequencies [Echternach et al., 2011, JASA 129]. Research on supralaryngeal articulator differences, specifically midsagittal tongue shape differences, during this transition is limited. Our previous case study showed a higher tongue dorsum in head voice for low and mid vowels compared to chest voice [Bengtson et al., 2023, CAA 51]. The current study with ten participants (8 female, 1 non-binary, 1 male, aged 19–23) further explores this and the effect of the years of vocal training. Participants were recorded performing a chromatic scale through their register transition, followed by a whole-tone scale in each register, with both tasks repeated twice on each of seven vowels (/a, e, o, ɚ, i, u, y/). The hypothesis is that vowel-dependent tongue adjustments would be observed, with more experienced singers displaying smaller differences between registers. Tongue shapes were traced using DeepEdge, and target frames were extracted [Chen et al., 2020, ISSP 2020]. Preliminary analysis indicates that the tongue dorsum is lower for chest voice and for participants with more years of voice training.