Neural correlates of single word reading in bilingual children and adults

•Bilingual children and adults brain activity was measured for single word reading in Spanish and English.•Adults showed better performance on language proficiency measures in English but not Spanish relative to children.•Both children and adults showed activity in classic language areas.•Greater activity in adults was revealed in the middle temporal gyrus.•Age-related differences were greater in English than Spanish. The present study compared the neural correlates of language processing in children and adult Spanish–English bilinguals. Participants were asked to perform a visual lexical processing task in both Spanish and English while being scanned with fMRI. Both children and adults recruited a similar network of left hemisphere “language” areas and showed similar proficiency profiles in Spanish. In terms of behavior, adults showed better language proficiency in English relative to children. Furthermore, neural activity in adults was observed in the bilateral MTG. Age-related differences were observed in Spanish in the right MTG. The current results confirm the presence of neural activity in a set of left hemisphere areas in both adult and child bilinguals when reading words in each language. They also reveal that differences in neural activity are not entirely driven by changes in language proficiency during visual word processing. This indicates that both skill development and age can play a role in brain activity seen across development.