Evaluation of Tongue Pressures During Speech

Abstract

In order to investigate pressures against the dentition during the formation of selected linguo-alveolar and linguo-palatal consonant sounds, strain gage pressure transducers were placed so as to allow simultaneous recordings: (1) under the upper lip, on the labial surface of the maxillary central incisors, (2) lingual to the maxillary central incisors, (3) lingual to the maxillary first molar. Speech evaluation by expert listeners was used to evaluate distortion produced by the presence of intra-oral transducers. Introduction of transducers caused a slight but insignificant decrease in articulatory precision. Lip pressures for all subjects during these consonant sounds were nonexistent or negligible. Light pressure against the lingual anterior transducer, ranging typically from less than 10 to 25 gm/cm2, usually accompanied speech. Pressure was applied to the lingual molar transducer during the formation of all consonant sounds studied. Average molar speech pressures for the individual subjects ranged from 4 to 33 gm/cm2. Differences between mean pressures for the different consonants were in most instances not significant. Whether a sound occurred in the initial or final position in a syllable did not seem to affect the pressure associated with its formation. It was concluded that tongue pressures of appreciable magnitude may be placed against the dentition during the formation of consonant sounds. A technique similar to that described in this paper offers a new approach to quantitative studies of tongue pressure and tongue placement during speech.