A magnetoencephalographic study on auditory processing of native and nonnative fricative contrasts in Polish and German listeners.

Linguistic experience shapes auditory processing of speech sounds as indicated by the mismatch negativity (MMN). In the current study, magnetic mismatch fields (MMNm) in response to native and nonnative fricative-vowel syllables were recorded, using whole-head magnetoencephalography (MEG). Earlier difference waves were enhanced in the left hemisphere in native listeners for fricatives with rather subtle acoustic differences in frication and pronounced acoustic differences in the transition to the vowel. For nonnative subjects, difference waves were at first stronger in the right hemisphere for these contrasts. Left hemispheric MMNms only occurred later in nonnative participants. The results are discussed in relation to previous studies suggesting lateralization of speech sound processing.