From the 1960s to the early 21st century, different terms have arisen in diverse research traditions and educational contexts where teachers and researchers are interested in exploring and researching ways of helping learners to learn both language and content at the same time. These terms include content-based instruction (CBI), immersion, sheltered instruction, language across the curriculum (LAC), writing across the curriculum (WAC), and content and language integrated learning (CLIL). Common to all these traditions, however, is the monoglossic and monolingual assumption about academic language and literacy. The dynamic process turn in applied linguistics has changed our view of the nature of language, languaging, and language learning processes. These new theoretical insights led to a transformation of research on LAC toward research on academic languages and literacies in the disciplines. A paradigm shift from monoglossic to heteroglossic assumptions is also particularly important in English-as-an-additional-language (EAL) contexts.