To investigate the influence of velopharyngeal (VP) port area on the perception of oral stop versus nasal consonants in child-sized vocal tracts.
Design
C1VC2 words were generated using a computational model scaled to 4-, 6-, and 8-year-old vocal tracts. VP coupling area was systematically varied along a continuum from 0 to 0.1 cm2. Stimulus presentation was randomized and presented in a forced-choice perceptual identification task with 4 response options reflecting consonant differences.
Setting
University laboratory.
Participants
Thirty untrained adult listeners.
Intervention
Incremental increases in VP coupling area.
Main Outcome Measures
Listener identification of oral versus nasal consonants.
Results
Across all vocal tract ages and vowel contexts (/æ, ɪ, u/), crossover areas at which listeners perceived a nasal instead of an oral stop ranged from 0.014 to 0.035 cm2. A one-way multivariate analysis of variance revealed a significant effect of talker age on overall vowel measures, with post hoc tests showing 4-year-olds had smaller crossover areas than older children for /æ/. Crossover areas for child vocal tracts were smaller than those reported for adults (∼0.045-0.046 cm2). Variability across vowels and ages, particularly in younger talkers, indicated broader perceptual ambiguity.
Conclusions
Small VP openings in child vocal tracts can produce perceptual cues typically associated with hypernasality, even at relatively modest gap sizes. These findings reflect developmental differences in speech production and may inform clinical management of VP insufficiency, emphasizing the perceptual impact of VP gap size on listener judgments.
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