Lateral bracing of the tongue during the onset phase of alveolar stops: an EPG study.

Although raising the sides of the tongue to form a seal with the palate and upper teeth--lateral bracing--plays a key role in controlling airflow direction, providing overall tongue stability and building up oral pressure during alveolar consonant production, details of this articulatory gesture remain poorly understood. This study examined the dynamics of lateral bracing during the onset of alveolar stops /t/, /d/, /n/ produced by 15 typical English-speaking adults using electropalatography. Percent tongue palate contact in the lateral regions over a 150-ms period from the preceding schwa to stop closure was measured. Rapid rising of the sides of the tongue from the back towards the front during the 50-ms period before closure was observed, with oral stops showing significantly more contact than nasal stops. This feature corresponds to well-documented formant transitions detectable from acoustic analysis. Possible explanations for increased contact for oral stops and clinical implications are discussed.