Acoustics of speech, articulatory compensation, and dental overjet in Cantonese

Abstract

Studies relating dental anomalies to misarticulations have noted that potential correlations appear to be obscured by articulatory compensation. Accommodation of tongue or mandible positions can help even individuals with severe malocclusion approximate perceptually typical speech [Johnson and Sandy, Angle Orthod. 69, 306-310 (1999)]. However, associations between malocclusion and articulation could surface if examined with acoustic analysis. The present study investigates the acoustic correlates of Cantonese speech as it relates to degree of overjet (horizontal overlap of upper and lower incisors). Production data was collected from native Cantonese-speaking adults, targeting the vowels /i, u, a/, and fricatives /f, s, ts, tsh/, previously found to be vulnerable phonemes in Cantonese speakers with dentofacial abnormalities [Whitehill et al., J Med Speech Lang Pathol. 9, 177-190 (2001)]. Measures of dental overjet and language background were included as well. Preliminary results from trained listeners show that productions were perceptually typical. Acoustic analysis consisted of spectral moments for fricatives and formant values for vowels. The results improve our understanding of the relationship between malocclusion, compensation and speech production in non-clinical populations.

Speech adapts to differences in dentition within and across populations

“…An ease-based bias for/against labiodentals should be evident in the speech of at least some individuals with distinct bites. Studies in linguistics have not considered the role of dental malocclusion on the speech of individuals, but some recent work by dentists and orthodontists has examined the role 37 – 39 . In one recent study, 115 patients were tested and it was found that an overbite exceeding only 2 mm can lead to multiple speech “errors” 37 .…”