The effect of syllable repetition rate on vocal characteristics

This study examined whether mean vocal fundamental frequency (F0) or speech sound pressure level (SPL) varies with changes in syllable repetition rate. Twenty-four young adults (12 M and 12 F) repeated the syllables/p∧/,/p∧tə/, and/p∧təkə/at a modeled “slow” rate of approximately one syllable per second, at a self-selected “comfortable” rate, and at their maximum rate. For both male and female subjects there was a significant increase in F0, but not SPL, between the “slow” and “maximal” and between the “comfortable” and “maximal” repetition rates. Conversely, there was no significant difference in mean F0 associated with syllable type, whereas significant SPL differences were most likely due to differences in plosive aspiration, syllable stress, and juncture between the mono-, bi-, and tri-syllabic sequences. These results suggest that there is a laryngeal adjustment that attends an increase in speech rate, lending additional support for speech and voice treatment strategies that employ rate modification techniques.Learning outcomes: The reader will be able to: (1) outline the advantages and disadvantages of using a syllable-repetition task to evaluate speech rate; (2) describe how vocal F0 and speech SPL are affected by changes in speech rate; and (3) describe the clinical and theoretical implications of the results from this study.

► We examine changes in vocal F0 and speech SPL with varying syllable-repetition rate.
► There were no significant sex differences in syllable-repetition rate.
► There was a significant increase in F0, but not SPL, with higher repetition rates.
► There was a significant decrease in SPL, but not F, with bi- and tri-syllabic sequences.
► A laryngeal adjustment appears to accompany an increase in speech rate.