Speaker
Description
Malocclusion impacts articulation of speech sounds, in particular fricatives. The present study compares spectral and prosodic patterns between adults with and without jaw disharmony during production of the English sibilants /s/ and /ʃ/. 36 adult participants were recruited and categorized using the Angle Classification into control (Class I) and experimental (Class II and Class III) groups. Speech recordings were obtained using an iPhone in a clinical setting. Speech recordings were analyzed for first and second spectral moment (i.e., center of gravity (COG), and spectral dispersion), duration and intensity of the English sibilants /s/ and /ʃ/ using a linear mixed effects model. Significant differences in each acoustic variable were found between the malocclusion classes including prominent interactions with sex. Class III malocclusion exhibited more prominent acoustic spectral distortions followed by Class II. Class III females had the highest COG for /s/ and /ʃ/ along with longer duration. Class III males showed reduced acoustic distinction between the two sounds along with intensity changes. Compensatory speech strategies involving duration and intensity changes might be learned to mitigate the impact of malocclusion on speech sound distinctions. These findings underscore intricate relationships between jaw alignment and speech articulation.