Perceiving non-native speech

In a series of experiments using monosyllabic words produced by a native and a non-native speaker of English, native English speakers monitored the word-initial consonants of the words to decide which of two consonants was present on each trial. In some of the experiments, a secondary task of a linguistic nature, deciding whether the target-bearing word was a noun or verb, was also required. When the words were presented in silence, the native and non-native stimuli were processed in a like manner. Specifically, when the secondary task was not required, phonemic decisions tended to be made on the basis of prelexical information, whereas when the secondary task was required, they tended to be made on the basis of postlexical information (see Eimas, Marcovitz Hornstein, & Payton, 1990). However, when the listening conditions were degraded by presenting the words at a lower level and in noise, the two types of stimuli yielded different patterns. Native speech was processed as before, whereas for non-native speech phonemic decisions now tended to be made on the basis of postlexical information both when a secondary task was required and when it was not. The contrasting results for native and non-native speech are discussed in terms of models of phoneme processing.