AbstractThe present study analyzed lexical processing efficiency in Spanish-speaking English language learners (ELLs) and their monolingual English-speaking peers from kindergarten through second grade. Specifically, changes in the patterns of speed and accuracy on a rapid object-naming task were evaluated across languages for the ELL children and across the groups of children. Repeated measures analysis of variance demonstrated that ELL children have a rapid shift in language processing efficiency from Spanish to English by the end of kindergarten. Results also showed that by the end of kindergarten ELL children were slightly faster and more accurate in English compared with their monolingual peers. This work provides perspective on how lexical processing is impacted by the development of a dual lexical system. We discuss how lexical density, strength of lexical connections, and environmental constraints may influence this rapid shift in lexical processing efficiency for young Spanish-speaking ELL children.