During 1974–2001, the field coalesced around the idea that second language development is shaped by the learner's first language and social context, with cross-language transfer influencing literacy and achievement. The communicative turn emphasized meaningful use of language, comprehensible input, and low affective filters as drivers of acquisition, reshaping classroom practice toward authentic interaction and ongoing experimentation. Methodologically, researchers integrated classroom data with theoretical models, highlighting variability, learner differences, and dynamic development.