This study explores the framework and potential applications of Generative Artificial Intelligence (GAI) in language teaching and learning design, conceptualizing GAI as a tool, tutor, and tutee. From the language education and research perspective, we analyze the issues involved, with a particular focus on the core values of GAI and how it can enhance learner engagement. Firstly, the term GAI is explained, and its application is illustrated using real-life language learning contexts. The role of GAI as a tool, tutor, and tutee in the language learning process is discussed, and corresponding teaching strategies and examples are presented. In addition, GAI’s critical influence and potential practical applications in language learning design are especially highlighted. For example, GAI has proven its excellence in content generation and learning path enhancement, providing learners with personalized learning experiences and effectively increasing learner engagement. In language learning contexts, GAI not only provides timely feedback as a learning tool enriched with a variety of listening, speaking, reading, and writing materials, but also acts as a tutor, providing personalized learning paths to meet the specific needs of students. In addition, students are taught to reflect on and consolidate their language knowledge and skills through AI, reflecting the role of GAI as a tutee. In conclusion, we discuss the research issues that may arise from using GAI in language learning. As GAI technologies advance and find application, the potential use of GAI technologies in language learning may bring more innovation and issues to the language learning field.