Cross-linguistic lateral bracing: An ultrasound study

Abstract

Lateral bracing refers to intentional stabilizing of tongue contact with the roof of the mouth along the upper molars or the hard palate. Previous research has found evidence of lateral bracing in individual speakers of six languages [Cheng et al. 2017. Can. Acoust. 45, 186]. The current study examines lateral bracing cross-linguistically at a larger scale using ultrasound technology to image tongue movement. We tracked and measured the magnitude of vertical tongue movement at three positions (left, right, and middle) in the coronal plane over time using Flow Analyzer [Barbosa, 2014. J. Acoust. Soc. Am. 136, 2105] for optical flow analysis. Preliminary results across all languages (Cantonese, English, French, Korean, Mandarin, and Spanish) show that the sides of the tongue are more stable than the center and maintain a relatively high position in the mouth throughout speech. The magnitude of movement at the sides is significantly smaller than at the center of the tongue. Further, lateral releases vary in frequency for different languages. This evidence supports the view that bracing is a physiological property of speech production that occurs irrespective of the language spoken. [Funding from NSERC.]