The effect of speaking rate on velopharyngeal function in healthy speakers

The purpose of this study was to assess the effect of speaking rate variation on aerodynamic and acoustic measures of velopharyngeal (VP) function. Twenty-seven healthy adult speakers (14 males, 13 females) participated in the study. The modified pressure-flow method was used to collect aerodynamic data of /m/ and /p/ segments in the word 'hamper' and the utterances 'Mama made some lemon jam' (MMJ) and 'Buy Bobby a puppy' (BBP). SPL was collected simultaneously with aerodynamic data for all utterances. A Nasometer was used to obtain nasalance scores and nasalance distance for MMJ and BBP. Sentences were produced at normal, fast, slow, and slowest speaking rates. The results showed that nasal airflow and VP orifice area were unaffected by speaking rate variations in males and females, whereas intra-oral pressure appeared to decrease as speaking rate slowed for both speaker groups. However, this effect was removed by statistically controlling SPL. Nasalance and nasalance distance (MMJ-BBP) did not change with speaking rate variation. There was a statistical difference between nasalance scores produced by male and female speakers. The results suggested that aerodynamic and acoustic measures of velopharyngeal function are not affected by variation in speaking rate in healthy males and females.