Project Summary/Abstract Children who speak and read in two languages are the norm around the world and in many US communities. However, there is a gap in understanding how language and literacy develops in bilingual and biliterate children. A fundamental component of language and literacy development is word recognition. Central to both spoken and written word recognition is competition: given a word (e.g., cap), multiple lexical candidates are activated (e.g., cap, cab, cat) and compete for recognition. The nature of lexical competition within and across languages in children is largely unaddressed. This is a crucial limitation as prominent theories of bilingual language and cognition rest on how these skills develop. This is of clinical significance because for monolingual children, the ability to manage competition is highly predictive of language and literacy outcomes and represents significant challenges for children with language disorders (McMurray et al., 2010). Because there are health disparities that perpetuate disproportionate educational achievement for many Spanish- English learners in the US, it is crucial that our theoretical models extend beyond single-language learners, to students who hear and read words in more than one language. The proposed research addresses this limitation in two aims. In Aim 1, we characterize competition for spoken and written words within and across languages in Spanish-English dual language learners during a developmental period characterized by variability in word-level reading skills (middle school). We developed a novel variant of an eye-tracking paradigm to measure both spoken and written word recognition. Individuals hear or see a word and click the corresponding picture from a display of four: the target (e.g., cap), an acoustically and visually similar competitor (e.g., cab) and unrelated items (e.g., net and mud). Eye-movements are time-locked to the dynamics of lexical competition. Given that there are more differences in speech sounds than in letters across languages (e.g., the speech sound /b/ differs in English and Spanish, yet the letter “b” is identical), we predict that for spoken words, competition will be greater within than across languages, whereas for written words, competition will be similar within and across languages. In Aim 2, we take an individual differences approach and examine how language and reading proficiency influence these competition dynamics. This aim will determine the sources of variability that promote proficient bilingual and biliterate children to achieve efficient word recognition. The current research has a broad-based appeal for theories of language processing because it will help characterize a core set of computational principles involved in spoken and written word recognition. Further, this project informs theories of bilingual language and literacy development – a high priority research area for NICHD – and represents a crucial step toward our long-term...