GenAI-supported collaborative project-based language learning: effects on EFL undergraduates’ achievement and autonomy

Abstract Despite growing interest in Generative AI (GenAI) in language education, empirical evidence examining its pedagogical integration within project-based language learning and its influence on measurable learning outcomes remains limited. Many studies emphasize learner perceptions or short-term tool interaction rather than sustained classroom interventions grounded in instructional design. Addressing this gap, this explanatory sequential mixed-methods study investigated the extent to which participation in GenAI-supported collaborative PBLL was associated with changes in English language achievement and learner autonomy among EFL undergraduates. Participants were 53 Saudi female first-year university students assigned to experimental and control groups. Data were collected using parallel-form achievement tests, a researcher-developed learner autonomy questionnaire with exploratory construct validation, and thematic analysis of student reflections. Quantitative data were analyzed using linear mixed-effects modelling to examine differential change over time between groups. Results showed that GenAI-supported collaborative projects were associated with greater gains in overall English achievement, particularly in writing, vocabulary, and total scores compared with traditional instruction. Grammar improvement occurred in both groups, suggesting general course progression rather than a differential intervention effect. Learner autonomy development was also significantly greater in the experimental group across dimensions, with especially strong growth in motivation and self-regulation. Qualitative findings suggested that collaborative engagement, peer interaction, and GenAI-mediated scaffolding supported strategic learning behaviors, confidence, and reflective awareness, while highlighting challenges related to digital literacy, tool selection, and potential over-reliance on AI outputs. Overall, findings suggest that GenAI-supported PBLL may contribute to language development and autonomy when embedded within structured and socially mediated learning environments.