Lateral tongue bracing as a universal postural basis for speech

Lateral bracing refers to an intentional tongue posture whereby the sides of the tongue make contact with the sides of the palate and the upper molars. While previous research on this topic has focused mostly on English, the present study tests the hypothesis that lateral bracing provides a fundamental postural basis for speech and is present across languages. We predicted that, across multiple languages, the sides of the tongue should be more stable than the center and should stay in a relatively high position in the mouth throughout most of running speech. Using coronal ultrasound imaging, we measured tongue movement produced by speakers (N = 28) of six languages (Akan, Cantonese, English, Korean, Mandarin and Spanish). Across these languages, as predicted, the sides of the tongue throughout running speech were positioned higher in the mouth than the center, and the range of movement of the sides was significantly smaller than that of the center of the tongue. These findings support the view that the sides of the tongue maintain a braced posture across languages while speaking, potentially constituting a universal, rather than language-specific, postural basis for speech.