Investigating vulnerabilities in grammatical processing of bilinguals: Insights from Basque-Spanish adults and children

Abstract

Abstract Bilinguals show a large gap in their expressive-receptive abilities, in both languages. To date, most studies have examined lexical processing. The current study aimed to assess comprehension and production of verb agreement, i.e., grammatical processing, in bilinguals, and to examine the factors that might modulate them: exposure, age and language-specific morphological complexity. Twenty balanced Basque-Spanish bilinguals (10 adults and 10 children) were assessed on comprehension and production of subject-verb agreement in both languages and object-verb agreement in Basque. Twenty age-matched Spanish-dominant Basque-Spanish bilinguals were assessed in Spanish only. The results revealed a consistent gap in Basque in both children and adults, with an advantage for comprehension. In Spanish, a gap appeared in children only, with an advantage for production. The gap size did not vary with the amount of language exposure but with age and morphological complexity, suggesting that these factors modulate bilinguals’ grammatical processing.