Exploring the Bilingual Phonological Space: Early Bilinguals' Discrimination of Coronal Stop Contrasts

It is well known that the way monolingual listeners discriminate speech sounds is strongly influenced by their native (L1) sound system. Moreover, such perceptual constraints are not limited to monolinguals: multiple studies have found evidence of language-specificity in bilingual speech perception. However, the question of whether bilinguals have simultaneous access to both of their phonologies during non-native contrast discrimination has not been systematically examined. Namely, very few studies of bilinguals have specifically examined cases where a non-native contrast pair straddles the boundary between two sound systems, with one sound corresponding to a sound in the L1, and the other to a sound in the second language (L2), but with neither the L1 nor the L2 containing both. The current study aimed to do so by comparing the ability of early bilinguals to discriminate non-native phonetic contrasts consisting of sounds that exist in either their L1 or L2, but not in both. A forced-choice perception task compared two listener groups-Spanish-English bilinguals and English monolinguals-on their perception of Nepali dental-alveolar stop contrasts. Results showed that despite displaying some sensitivity to phonetic differences within each contrast pair, the bilingual group was unable to discriminate such "cross-language contrasts" significantly better than the monolingual English control group.