This study investigates children's changing sensitivity to processing cues foridentifying agent (word order, case marking, and animacy) as a function of proficiency in asecond language. English-speaking learners of Japanese need to appropriately adjust cuestrengths in moving from a rigid SVO language to one in which SOV word order is a goodgeneral processing strategy, but case marking must ultimately be relied on if it conflicts with thisorder. English-speaking children in grades K–7 in an immersion school were asked toidentify the agent for a set of audiotaped sentences in English and Japanese. The children in thisstudy learned to use SOV word order, lexical semantics, and canonical case marking, but they donot provide evidence of appropriately exploiting noncanonical case marking. We suggest thatthese results might be accounted for by the context in which input is processed in immersionschool classrooms.