This book investigates the acquisition of sociolinguistic knowledge in the early elementary school years of a Mandarin-English two-way immersion program in the United States. Using ethnographic observation and quantitative analysis of data, the author explores how input from teachers and classmates shapes students’ language acquisition. The book considers the different sociolinguistic messages conveyed by teachers in their patterns of language use and the variety of dialects negotiated and represented. Using analysis of teacher speech, corrective feedback and student language use, the author brings together three analyses to form a more complete picture of how children respond to sociolinguistic variation within a two-way immersion program.