Purpose: This study examined the relation between African American preschoolers' use of African American English (AAE) and their language and emergent literacy skills in an effort to better understand the perplexing and persistent difficulties many African American children experience learning to read proficiently. Method: African American preschoolers' (n = 63) vocabulary skills were assessed in the fall and their language and emergent literacy skills were assessed in the spring. The relation between students' AAE use and their vocabulary and emergent literacy skills was examined using hierarchical linear modeling (HLM), controlling for fall vocabulary and other child, family, and school variables. Children's use of AAE was examined across two contexts--sentence imitation and oral narrative using a wordless storybook prompt. Results: There was a significant U-shaped relation between the frequency with which preschoolers used AAE features and their language and emergent literacy skills. Students who used AAE features with greater or lesser frequency demonstrated stronger sentence imitation, letter-word recognition, and phonological awareness skills than did preschoolers who used AAE features with moderate frequency, controlling for fall vocabulary skills. Fewer preschoolers used AAE features during the sentence imitation task with explicit expectations for Standard American English (SAE) or School English than they did during an oral narrative elicitation task with implicit expectations for SAE. Conclusions: The nonlinear relation between AAE use and language and emergent literacy skills, coupled with systematic differences in AAE use across contexts, indicates that some preschoolers may be dialect switching between AAE and SAE, suggesting emerging pragmatic/metalinguistic awareness.