Modeling Intra- and Inter-individual Changes in L2 Classroom Engagement.

This article investigates the dynamic trajectories of student engagement and disengagement in second language (L2) English classrooms over a 17-week semester at two public universities in mainland China. Using longitudinal data from 686 non-language major students and multi-level mixed-effects growth curve modeling, the study found that engagement dipped mid-semester and peaked toward the end, while disengagement showed the opposite pattern. Changes in students' basic psychological needs—autonomy, competence, and relatedness—based on Self-Determination Theory (SDT) were significant predictors of these engagement trajectories, with need satisfaction linked to increased engagement and need frustration associated with increased disengagement. The findings highlight the situated, dynamic, and multidimensional nature of L2 learner engagement and underscore the importance of motivational antecedents in shaping engagement patterns over time.