Variations in Velopharyngeal Valving: The Factor of Vowel Changes

Abstract

A considerable amount of study regarding " normal " velopharyngeal valving as related to sound production in connected speech is yet to be completed, mainly because of the large number of variables involved in such investigations. Studies have shown that velopharyngeal valving for specific sounds is affected by the phonetic environment of the sound evaluated (3, 4, '7, 9). It has also been demonstrated that valving for sustained sounds is considerably different from valving on the same sounds in any connected speech utterance (9, 10). Since additional information is needed and because there are important clinical and theoretical applications for such descriptive in— formation on larger samples, a series of cinefluorographic investigations was designed to describe some relationships between velopharyngeal valving and the production of specific sounds as they occur in syllables in connected speech. The syllable, as described by Stetson (13) and, more recently, by J akobson and Halle (8), is considered in these studies to be the basic unit of motor speech production. With this frame of reference, controlled cinefiuorographic films were obtained to analyze movement patterns of the organs of speech from the trachea to the lips for 100 normal speaking subjects. Each film contains sets of syllables, a series of consonant-vowel-consonant words, and a sentence containing numerous nasal and oral consonants and a sampling of various types of vowel elements. This report is the first in the series of reports. The report is limited to an analysis of velopharyngeal valving for five normal subjects producing similar repeated CV syllables under controlled conditions. The vowels /i/, /a/, and /u/ were combined with the labial consonant /p/ to form the CV syllables analyzed. The questions asked were: a) Do significant differences in measurements of velopharyngeal valving occur as a result of vowel changes in utterances of repeated CV syllables? b) Does the temporal order of a syllable in an utterance affect the measurements of velopharyngeal