When children learn language, they learn more than sounds, words, and syntax: they learn how language can be used as a tool for constructing and performing social identities, for relating to others, and for otherwise communicating meaning beyond the literal. And yet, research on early child language learning has traditionally, and markedly, isolated itself from considerations of children’s simultaneous social and cultural development. This interdisciplinary team of developmental psychologists, linguists, and comparative developmentalists seeks to move past this artificial separation. The project brings together methods and theory from developmental psychology and sociolinguistics to examine language at its earliest intersection with social identity: the detection and learning of dialects by infants and young children. This high-risk project leans on the incredible dialect variation across Chicagoland communities to develop and road-test a cross-linguistic and cross-culturally applicable research method for testing children's early sound, word, and social knowledge of different dialects, including an artificial dialect designed to target specific aspects of the learning process. Given the novelty and potential impact of the proposed method, even partial success would make a substantial contribution to our currently limited insight into the very beginnings of children’s knowledge about social variation in language, both generally and with respect to Chicago dialects specifically.