Plosive Phoneme Duration as a Function of Palato-Pharyngeal Adequacy

Abstract

One interesting and seldom mentioned speech phenomenon related to impaired palatopharyngeal function is a breakdown in consonant boundaries with a subsequent increase in plosive phoneme duration. This problem is easily identified through broad band spectrographic analysis (4). If it can be assumed that adequate intra—oral air pressure during speech production is the primary factor responsible for proper articulation of the plosive phoneme and if this buildup of air pressure is the result of ade— quate palatopharyngeal function, then the prospect of what happens to these plosive phonemes during palatopharyngeal inadequacy can become an important question. It would be of interest to observe the duration characteristics of these sounds in relation to palatopharyngeal adequacy. A pilot study was carried out (4) which consisted of the measurement of the duration characteristics of the plosive phonemes /p, t, k/ as pro— duced by three subjects wearing palatal lift prosthetic appliances designed to aid in palatopharyngeal function. The sound spectrograph was utilized to make duration measurements of those utterances produced while the subjects wore their appliances and then removed them. In all cases the duration measurements of the plosive phonemes for the appliance—in condition were less than those of the appliance-out condition. This pilot study suggested the need for further analysis of plosive phoneme duration. Except for this study, the use of the sound spectrograph to measure plosive phoneme duration with respect to palatopharyngeal adequacy has not been proposed in the literature. Although Gibbons and Bloomer (2) noted a number of consonant changes on a spectrogram representing nasal speech, no direct mention of increased phoneme duration was made. This study, then, has been designed to investigate the phenomenon of plosive phoneme duration in the presence of palatopharyngeal insuffi— ciency, created by removal of oral prosthetic appliances designed to aid in palatal function. As a secondary objective, the study attempted to evalu— ate the effectiveness of the oral prosthetic appliance in the treatment of palatopharyngeal malfunction. Procedure SUBJECTS. Twenty subjects were utilized for this study. They ranged in age from 17 to 72 years with a mean age of 47 years. All wore palatal 65