Influence of Voice Focus on Oral-Nasal Balance in Speech

Abstract

The concept of voice focus describes the relationship of the vocal tract length on the perceived brightness or darkness of the speaker's voice. The present study explored the impact of adjustments of the voice focus on oral-nasal balance. The vocal tract settings in question were backward focus (retracted tongue, wide pharynx, and lowered larynx) and forward focus (fronted tongue, constricted pharynx, and raised larynx). The backward focus condition was expected to decrease nasalance scores and the forward focus condition was expected to increase nasalance scores. Experimental repeated-measures study. Sixteen females aged 23.78 (standard deviation 1.99) produced oral and nasal test sentences with a backward focus and a forward focus. Audio recordings and nasometry measurements were made. Nine of the participants completed the task successfully. In a repeated-measures analysis of variance, the nasalance scores were compared across stimuli, speaking condition, and repetition. There was a main effect for stimuli (F = 109.37, P < 0.0001). In a follow-up analysis of variance we found a condition effect for the nasal stimulus (F = 17.91, P < 0.0001). For the nasal stimulus, the nasalance scores of the backward focus were lower, and the nasalance scores of the forward focus were higher than in the normal condition. Changing the voice focus influenced oral-nasal balance more when the velopharyngeal port was open. Future studies should explore the possible treatment potential of voice focus for patients with hypernasality.