Acoustic Features of Pharyngeal /s/ Fricatives Produced by Speakers with Cleft Palate

Abstract

The production of pharyngeal fricatives represents one type of compensatory speech maneuver exhibited by speakers with palatal clefts. Several investigators have observed that some speakers with cleft palate substitute pharyngeal fricatives for consonants normally produced in the front of the mouth (1, 8). Although pharyngeal consonants have long been known to be present in the speech of certain cleft palate speakers, their acoustic correlates are not well understood. As their label implies, pharyngeal fricatives are produced by approxi— mating the tongue to the pharyngeal wall (7). Subtelny (10) has recently provided radiographic evidence that pharyngeal consonant gestures used by speakers with cleft palate are accomplished by retracting the tongue dorsum to the pharyngeal wall, thereby producing a primary constriction in the lower pharynx. It is of considerable importance to note that pharyngeal fricatives are normally not produced by speakers of English. Rather, fricatives are normally produced by forming a primary constriction in the mouthwthat is, at loci between the velum and the lips. There are, however, several languages that employ pharyngealized consonant gestures. Klatt (6') and Stevens (.9) have recently examined the acoustic properties of pharyngeal consonants produced by Arabic speakers. Their data indicate that pharyn— geal consonants are characterized by a set of distinctive acoustic features and that these features differ markedly from those associated with con— sonants produced in the front of the mouth. Specifically, Klatt (6) and Stevens (9) have shown that the pharyngeal consonant productions of Arabic speakers exhibit " the distinctive property that F1 is high and rela— tively close to F2. This property distinguishes pharyngeal consonants from those produced with a more anterior constriction position, all of which are characterized by a low-frequency first formant. " In addition, Klatt and The authors are affiliated with the