The Effects of Changes in Speaking Rate on Nasal Airflow and the Perception of Nasality

Abstract

The effects of variation in speaking rate on relative nasal airflow (percent nasal flow) and on the perception of nasality were examined. In addition, the effects of gender and speech rate elicitation techniques (metronome-controlled, self-controlled) were examined. Nineteen normal speakers each produced a stimulus phrase containing nonnasal sounds. Oral and nasal airflows were measured using the Rothenberg aerodynamic system. Results indicated that percent nasal flow and perception of nasality were both greater at slow speaking rates compared to normal and fast rates. Males were perceived as more nasal than females. The metronome-controlled rates were associated with greater nasality than the self-controlled rates. Discussion focuses on physiological correlates to these findings.

The effect of speaking rate on velopharyngeal function in healthy speakers

“…Based on Fletcher and Daly's finding that nasalance increased as speaking rate slowed (1976) and the consistent reports that perceived nasality increased at slow speaking rates (Brancewicz & Reich, 1989;Colton & Cooker, 1968;Goberman et al, 2001), it was expected that nasalance may increase as speaking rate slows for both oral and nasal sentences in the present study.…”

“…The study revealed an increase in peak nasal airflow and percent nasal airflow at slow as compared to normal and fast speaking rate conditions (Goberman et al, 2001). …”

“…Based on this observation, nasal airflow might be expected to increase at fast speaking rates due to the presumable increase in VP opening available for nasal air escape. The opposite occurred in the one published aerodynamic study however, in which nasal airflow did not differ between normal and fast speaking rates but increased at slow speaking rates (Goberman et al, 2001). Note that only one study has examined the effect of purposefully slowed speech on kinematic measures of VP function (Moll & Shriner, 1967).…”

“…To my knowledge, only one study investigated the effect of speaking rate manipulation on aerodynamic measures of VP function in healthy speakers (Goberman, Selby, & Gilbert, 2001). The authors studied the effect of self-controlled and metronomecontrolled speaking rate variation on peak nasal airflow rates and percent nasal airflow during schwa in the non-nasal sentence "it's a story about a park" in 19 healthy speakers.…”

“…While the difference in test utterances used between studies makes comparisons difficult, results from the two studies which assessed the effect of speaking rate on vowels are conflicting (Goberman et al, 2001;Moll & Shriner, 1967). Work by Moll and Shriner (1967) showed that velar elevation decreased for vowels at fast speaking rates due to velar undershoot.…”