Artificial intelligence-mediated informal digital learning of English (AI-IDLE) is a rapidly emerging subfield of computer-assisted language learning that focuses on autonomous, self-directed second language (L2) English development through AI tools beyond the classroom. Extending the established research agenda on informal digital learning of English (IDLE), AI-IDLE responds to a changing context in which AI technologies and digital platforms with embedded AI functionalities are reshaping the ecology of informal language learning. This Element provides the first comprehensive synthesis of AI-IDLE research and practice, grounded in an integration of proactive language learning theory and cultural-historical activity theory. It examines key antecedents and outcomes of AI-IDLE and, through original case studies, illustrates how learners negotiate resources and navigate diverse sociotechnical environments to engage in AI-IDLE. The Element concludes by outlining pedagogical strategies for supporting AI-IDLE and identifying future research directions for advancing this nascent field.
