Lexical category differences in bilingual picture naming: Implications for models of lexical representation

Bilingual speakers are less accurate and slower than monolinguals in word production. This bilingual cost has been demonstrated primarily for nouns. This study compared verb and noun retrieval to better understand bilingual lexical representation and test alternate hypotheses about bilingual cost. Picture naming speeds from highly proficient English–Spanish bilinguals showed a smaller bilingual cost for verbs compared to nouns. In Experiment 1, picture naming speeds were influenced by name agreement, age-of-acquisition and word length. Additionally, noun (but not verb) naming speed was predicted by word frequency. Experiment 2 examined two potential explanations for the smaller bilingual cost for verbs: verbs experience weaker cross-language interference (measured by translation speed) and smaller frequency effects. Both these predictions were confirmed, showing crucial differences between verbs and nouns and suggesting that cross-language facilitation rather than interference influences bilingual lexical retrieval, and that the frequency lag account of bilingual cost is more applicable to nouns than to verbs. We propose a Bilingual Integrated Grammatical Category model for highly proficient bilinguals to represent lexical category differences.