Do eye movements reveal differences between monolingual and bilingual children's first-language and second-language reading? A focus on word frequency effects

An extensive body of research has examined reading acquisition and performance in monolingual children. Surprisingly, however, much less is known about reading in bilingual children, who outnumber monolingual children globally. Here, we address this important imbalance in the literature by employing eye movement recordings to examine both global (i.e., text-level) and local (i.e., word-level) aspects of monolingual and bilingual children's reading performance across their first-language (L1) and second-language (L2). We also had a specific focus on lexical accessibility, indexed by word frequency effects. We had three main findings. First, bilingual children displayed reduced global and local L1 reading performance relative to monolingual children, including larger L1 word frequency effects. Second, bilingual children displayed reduced global and local L2 versus L1 reading performance, including larger L2 word frequency effects. Third, both groups of children displayed reduced global and local reading performance relative to adult comparison groups (across their known languages), including larger word frequency effects. Notably, our first finding was not captured by traditional offline measures of reading, such as standardized tests, suggesting that these measures may lack the sensitivity to detect such nuanced between-group differences in reading performance. Taken together, our findings demonstrate that bilingual children's simultaneous exposure to two reading systems leads to eye movement reading behavior that differs from that of monolingual children and has important consequences for how lexical information is accessed and integrated in both languages.