Oral and nasal vowels effects on subglottal pressure

Abstract

This paper investigates the effect of oral and nasal vowels on subglottal pressure. The vowels /i, e, a, o, u, ø, œ̃, õ/ were produced on a specific tone by two Belgian French speakers (male and female). The tone frequency was given to the speakers while producing the vowels through a set of headphones connected to a synthesizer. Three frequencies were given at comparable intensities (male speaker: A, C, E; female speaker: C, F, A). Both speakers produced the set of vowels in a mask, with the mouth at a quasi-constant distance from the microphone. In addition to the acoustic signal, the subglottal pressure was recorded by tracheal puncture with a needle inserted between the cricoid cartilage and the first tracheal ring. Measurements show that both speakers produced each of the vowels with stable F0 (2 Hz difference variation from the given tone). One interesting observation is that there is a substantial difference in subglottal pressure between oral and nasal vowels. Both speakers produced nasal vowels with a lower subglottal pressure when compared to oral vowels. Mean differences between both set of vowels were quantified at 2.15 hPa. Nasal vowels were found to have lower intensity than oral vowels.