Effect of the glottic co-articulation on the intra-ora

Abstract

Among different speech disturbances, postoperative cleft palate subjects with velopharyngeal insufficiency (VPI) present inability to build up enough intraoral air pressure (Po) during plosive consonants production; as a consequence, they often substitute a coarticulated glottal stop for the usual oral stop. In the present study, Po was determined during the production of the voiceless bilabial plosive /p/ in a syllabic context, by using a simple, non invasive instrumental method, in order to investigate the aerodynamic effects of the glottal articulation. Results indicated that in VPI patients the glottal stop produced in combination with lip articulation causes peculiar changes in the Po curve. In addition the effect of nasal mechanical occlusion (simulating surgical VPI correction) and of rapid syllabic production ( simulating conversational speech) on the Po characteristics of /p/ and on glottal stop occurance have also been studied. The findings provide support to the view that the analysis of Po may be used as an objective method for research and clinical assessment of glottal coarticulation during speech production.