Integrating ChatGPT for vocabulary learning and retention: A classroom-based study of Saudi EFL learners

Grounded in Vygotsky's sociocultural theory, this study examines the effectiveness of integrating ChatGPT into classroom instruction to enhance vocabulary learning. It evaluates ChatGPT's impact on vocabulary knowledge and retention compared to traditional teacher-led instruction. Using a quasi-experimental pre- and posttest control group design within an explanatory sequential mixed-methods approach, 71 EFL learners were randomly assigned to an experimental group (EG) and a control group (CG). The EG used ChatGPT as an interactive language tool, engaging in vocabulary practice, receiving real-time feedback, and completing AI-generated exercises tailored to their progress, while the CG followed traditional lecture-based instruction. Data collection included vocabulary knowledge tests (pretest, posttest, and delayed posttest) and semi-structured interviews. Quantitative results showed that the EG significantly outperformed the CG in productive vocabulary knowledge and overall test scores, with moderate to large effect sizes. While receptive vocabulary gains did not differ significantly between groups, within-group comparisons confirmed substantial improvements. Qualitative findings highlighted students' positive perceptions, emphasizing ChatGPT's role in enhancing engagement, motivation, and contextual vocabulary use through scaffolded interaction. This study contributes to the growing field of AI-driven language learning by demonstrating how structured, theory-informed integration of ChatGPT can effectively support productive vocabulary development, offering both practical and pedagogical insights.