Perception of native and non-native affricate-fricative contrasts: cross-language tests on adults and infants.

Previous studies have shown improved sensitivity to native-language contrasts and reduced sensitivity to non-native phonetic contrasts when comparing 6-8 and 10-12-month-old infants. This developmental pattern is interpreted as reflecting the onset of language-specific processing around the first birthday. However, generalization of this finding is limited by the fact that studies have yielded inconsistent results and that insufficient numbers of phonetic contrasts have been tested developmentally; this is especially true for native-language phonetic contrasts. Three experiments assessed the effects of language experience on affricate-fricative contrasts in a cross-language study of English and Mandarin adults and infants. Experiment 1 showed that English-speaking adults score lower than Mandarin-speaking adults on Mandarin alveolo-palatal affricate-fricative discrimination. Experiment 2 examined developmental change in the discrimination of this contrast in English- and Mandarin-leaning infants between 6 and 12 months of age. The results demonstrated that native-language performance significantly improved with age while performance on the non-native contrast decreased. Experiment 3 replicated the perceptual improvement for a native contrast: 6-8 and 10-12-month-old English-learning infants showed a performance increase at the older age. The results add to our knowledge of the developmental patterns of native and non-native phonetic perception.