The large and growing numbers of English language learners (ELLs) in U.S. schools and their persistent underachievement has focused attention on how best to educate students who are not only learning the language of English but are also learning the content of subjects such as math, science, social studies, and language arts in a new language. By definition, ELLs are not yet proficient in English. Learning new concepts, information, and skills in a new language presents significant cognitive and linguistic challenges. This entry provides a historical overview of teaching content and language and then discusses specific types of approaches for teaching language and content. Some models, such as the cognitive academic language learning approach (CALLA) and the Sheltered Instruction Observation Protocol (SIOP) model, have a ...