Perception of native and non-native phonemic contrasts in children with autistic spectrum disorder: effects of speaker variability

The current study investigated speech perception in children with ASD by directly comparing discrimination accuracy of phonemic contrasts in the native and non-native languages. The effect of speaker variability on phoneme perception was also examined. We also explored the relation between language impairment and accuracy in phoneme discrimination in children with ASD. Significant differences in performance were found between the ASD and TD groups on discrimination of the native phonemic contrasts. By contrast, no difference was found between the two groups on discrimination of the non-native phonemic contrasts. Further subgroup analysis revealed that the ALN group (ASD without language delay or impairment) showed significantly higher discrimination accuracy for the native syllable contrasts than the non-native counterpart. No significant difference was found in the discrimination accuracy between the native and non-native phonemic contrasts in the ALD group (ASD with language delay or impairment). The effect of speaker viability on phoneme discrimination was observed in the TD group but not in the ASD subgroups. Nonverbal reasoning ability was highly related to discrimination accuracy of both the native and non-native phonemic contrasts in children with ASD. The results of the present study suggest that speech perception in children with ASD is not as attuned to their native language as in their TD peers. Our findings also indicate that language delay or impairment is related to difficulty in perception of native phonemes in children with ASD.