Tongue-Palate Contact during Selected Vowels in Normal Speech

Abstract

Previous research using electropalatography has revealed that high vowels are vulnerable to articulation errors in cleft palate speech. The error involves complete tongue-palate contact, which obstructs normal airflow through the mouth and increases nasal airflow. This study used electropalatography to provide a more detailed description of typical tongue-palate contact for high vowels than currently exists. Electropalatography and acoustic data were recorded for multiple repetitions of monophthongs /i/, /u/, and /a/ and diphthongs /ai/, /oi/, and /au/. Ten typical English-speaking adults. Two measures were taken from electropalatography data during vowels; one identified electropalatography patterns with complete tongue-palate contact and a second calculated percentage of contact at five time points. None of the vowels had electropalatography patterns with complete tongue-palate contact. The amount of contact varied for the different vowels at the five time points throughout the vowels and also between speakers. When contact occurred, it was located in the posterior, lateral regions of the palate, forming a central groove that was free of contact. Complete tongue-palate contact during vowels is not a feature of typical English speech and can be considered an error pattern. The normative date provided in this study will be useful to speech-language pathologists who use electropalatography in their clinical work. The implications of the findings are discussed in relation to the assessment of vowels in cleft palate speech.