Intrinsic velocity differences between larynx raising and larynx lowering

• Published in: PloS one 2023-02, Vol.18 (2), p.e0281877
• Main Authors: Kleiner, Christian, Häsner, Patrick, Birkholz, Peter
• Format: Article
• Language: English
• Subjects: Biology and Life Sciences; Biomechanics; Female; Humans; Kinematics; Laryngology; Larynx; Larynx - diagnostic imaging; Male; Mechanical properties; Medicine and Health Sciences; Movement; Phonetics; Physical Sciences; Pitch; Realism; Research and Analysis Methods; Social Sciences; Speaking; Speech; Speech rate; Speech recognition; Speech synthesis; Thyroid gland; Ultrasonic imaging; Velocity; Vertical orientation; Videotape Recording; Vowels
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0281877

In this study, 23 subjects produced cyclic transitions between rounded vowels and unrounded vowels as in /o-i-o-i-o-…/ at two specific speaking rates. Rounded vowels are typically produced with a lower larynx position than unrounded vowels. This contrast in vertical larynx position was further amplified by producing the unrounded vowels with a higher pitch than the rounded vowels. The vertical larynx movements of each subject were measured by means of object tracking in laryngeal ultrasound videos. The results indicate that larynx lowering was on average 26% faster than larynx raising, and that this velocity difference was more pronounced in woman than in men. Possible reasons for this are discussed with a focus on specific biomechanical properties. The results can help to interpret vertical larynx movements with regard to underlying neural control and aerodynamic conditions, and to improve movement models for articulatory speech synthesis.