An Aerodynamic Study of the Articulatory Mechanism in the Production of Bilabial Stop Consonants

Abstract

In order to assess the velopharyngeal sphincter function during speech, the simultaneous registrations of the nasal air flow rate, the volume of the emitted air through the nose, the nasal air pressure, the oral pressure and the speech sounds have been attempted. The results of the present study on the articulatory mechanism of the bilabial stop consonants indicate the technique is reliable and promising for the accurate assessment of the articulatory processes, especially velopharyngeal sphincter function during speech. On the basis of detailed analyses of one hundred eighty utterances obtained from two normal subjects, the following conclusions are suggested : 1. During the production of bilabial stop consonants, the velopharyngeal space usually remains open until the oral pressure rises to a certain extent. The maximum velopharyngeal sphincter action is achieved when the oral pressure is elevated above a certain level. 2. Voiceless bilabial stop /p/ is produced with higher oral pressure rise of longer duration. The voiced bilabial stop /b/ undergoes a more rapid rise of the oral pressure of lower peak. 3. The production of the voiceless bilabial stop /p/ showed a tighter closure of the velopharynx than the voiced stop /b/.