An ultrasound study of tongue position during Hindi laryngeal contrasts

Initiating or maintaining phonation during stop closure involves several adjustments, including tongue root advancement to enlarge oral cavity volume (Westbury 1983). Ultrasound imaging shows that in English, the tongue is more advanced for phonologically voiced stops, whether phonated or unphonated (Ahn 2015). The current study uses ultrasound to examine tongue positioning during Hindi stops. Hindi has a unique four-way laryngeal contrast: voiced, murmured, voiceless unaspirated, and voiceless aspirated. Eight native Hindi speakers recorded phrase-initial stops at three places of articulation (labial, dental, velar) followed by the low vowel /a/. Results show a clear distinction in tongue position between voiced and voiceless unaspirated/aspirated stops. The tongue root is advanced for voiced stops in comparison to voiceless stops. However, there is no difference in tongue root position between voiceless unaspirated and aspirated stops. Murmured stops showed variation among speakers in comparison to other stops, while the majority of speakers show more advanced tongue root compared to voiceless stops. The results suggest that tongue root advancement facilitates phonation in Hindi. Thus, in Hindi, tongue root position corresponds to a phonological distinction in phonation most notably between voiced unaspirated stops and voiceless stops, whereas in English, tongue root position reflects a more abstract phonological distinction in voicing that does not correspond to phonation.