Effects of nasal port area on perception of nasality and measures of nasalance based on computational modeling.

OBJECTIVE: This study examined the relation between nasal port area, nasalance, and perceptual ratings of nasality for three English corner vowels, /i/, /u/, and /a/. DESIGN: Samples were simulated using a computational model that allowed for exact control of nasal port size and direct measures of nasalance. Perceptual ratings were obtained using a paired stimulus presentation. PARTICIPANTS: Four experienced listeners. MAIN OUTCOME MEASURES: Nasalance and perceptual ratings of nasality. RESULTS: Findings show that perceptual ratings of nasality and nasalance increased for samples generated with nasal port areas up to and including 0.16 cm(2) but plateaued in samples generated with larger nasal port areas. No vowel differences were noted for perceptual ratings. CONCLUSIONS: This work extends previously published work by including nasal port areas representative of those reported in the literature for clinical populations. Continued work using samples with varied phonetic context and varying suprasegmental and temporal characteristics are needed.