The concept of academic language (also referred to as academic English) has developed substantially in the 30years since Cummins introduced the distinction between basic interpersonal communication skills (BICS) and cognitive academic language proficiency (CALP). Cummins' (1979, 1981, 2000a) work explains why English language learners (ELs) may acquire basic conversational fluency in English quickly but require substantially longer to acquire academic language. The BICS/CALP framework has also influenced pedagogy, particularly by promoting highly contextualized teaching of academic content. More recent work drawing on linguistic approaches, including corpus linguistics and Systemic Functional Linguistics (SFL), provides insights into the specific features of language used in school settings. Pedagogical approaches emphasizing explicit language instruction and plentiful opportunities for oral and written language practice show promise for assuring that ELs can develop academic language proficiency. Given the need to address the academic achievement of the growing population of ELs, it is important for teachers to expand their concept of academic language instruction to include these approaches.