Language dominance influences bilingual lexical selection quantitatively but not qualitatively in language production: Evidence from Chinese-English bilinguals

• Language dominance influences bilingual lexical selection quantitatively but not qualitatively. • Computational models of L1 and L2 lexical selection are constructed. • The within-language competition view is extended to different script bilinguals. Previous research on bilingual lexical selection has mainly investigated the influence of the dominant first language (L1) on the speech production of the non-dominant second language (L2). However, research in the reverse direction is quite rare. Here we examined the influence in both directions using a bilingual picture-word interference (PWI) paradigm, where Chinese-English bilinguals named pictures in one language while ignoring distractors presented in another language. In both L1 and L2 naming, naming times were longer when distractors were semantically related to the picture names than when they were unrelated, resulting in a between-language semantic interference effect. In contrast, naming times were shorter when distractors were translations of the picture names than when they were unrelated, resulting in a translation facilitation effect. The results suggested that the mechanism of lexical selection in language production was in line with the within-language competition theory, showing no qualitative differences in the mechanism between L1 and L2. At the same time, the semantic interference effect sizes were not significantly different in L1 and L2 production, but the translation facilitation effect size was significantly larger in L2 production than in L1 production, indicating there exist quantitative differences in the mechanism of lexical selection between L1 and L2. A computational model was constructed to simulate naming performance and confirmed the accuracy of the within-language competition view in L1 and L2 lexical selection for Chinese-English bilinguals. We concluded that language dominance influences bilingual lexical selection quantitatively but not qualitatively in bilingual language production.