2011/01/05

Schmid, P. M. & Yeni-Komshian, G. H. (1999). The effects of speaker accent and target predictability on perception of mispronunciations. Journal of Speech, Language, and Hearing Research, 42, 56–64.

Presentation: Sarah

Summary: Sally

Intelligibility of nonnative speech has been investigated via different ways. Measurements based on accuracy of transcription by natives showed that accent ratings were not predictive of nonnative speakers’ intelligibility (Derwing & Munro, 1997; Munro & Derwing, 1995). Adapted from Cole’s method (1973 & 1980), the listening-for-mispronunciations task was first employed for nonnative speech in this study. During the task, mispronunciations (MPs) produced in the fluently articulated contexts were detected. Previous studies on native speech showed that MPs were more accurately detected when they were in predictable words, stressed syllables, and word-initial positions (Morton & Long, 1976; Cole & Jakimik, 1980; Cole et al., 1978).

In this study, 48 native listeners listened to native (N=4) and nonnative (N=4) production of English sentences. Among these sentences, target words were either of high or low predictability based on the context of the preceding words. All MPs were in word-initial position, with the target phonemes (6 stop sounds: /b/, /p/, /d/, /t/, /g/, /k/) manipulated for voicing, and place and manner (either fricative or nasal) of articulation. Results showed that the effect of sentence predictability was only significant in nonnative speech. Interaction between this factor and the effect of phonetic changes was also significant, as more MPs were detected in high-predictability sentences, especially for place and nasal changes. In addition, the effect of degree of accent was also observed: Native listeners were more accurate and faster in detecting MPs produced by native speakers. Based on a separate accent-rating task, the nonnative speakers were further divided into two groups; MPs produced by those with mild-to-moderate accents, were more accurately detected than MPs produced by those with a strong accent. Given that some sentences produced by nonnative speakers might not be equally comprehensible, and native listeners might adapt their expectations of acceptability in relation to speakers’ degree of accent, the authors concluded that intelligible but accented speech requires increased processing effort, which makes MPs not as detectable in nonnative speech.