Exploring EFL learners’ vocabulary learning in a longitudinal mobile-assisted context

Abstract Mobile-assisted vocabulary learning (MAVL) provides flexible, multimodal support for EFL vocabulary development, yet its effectiveness heavily depends on learners’ self-directed learning (SDL). Prior research has rarely examined learners’ longitudinal vocabulary learning behaviours and how they are associated with SDL. This study therefore investigates vocabulary learning outcomes and usage patterns over time in an MAVL environment. Drawing on Garrison’s SDL model, this mixed-method study collected data from 11 learners through daily self-reports, an SDL questionnaire, pre-test and post-test, a usage perception survey and semi-structured interviews over a 90-day app-based vocabulary learning period. The t -test results revealed a significant improvement in vocabulary knowledge following app use ( p < 0.05), although learners’ engagement levels and usage patterns varied substantially. Correlational analyses found no significant relationship between learning outcomes and motivation, self-management and self-monitoring. Interview results found users’ varied evaluations of the application’s design, embedded vocabulary pedagogy and how their SDL was influenced. Findings indicate the vocabulary learning application’s inability to support learners’ monitoring, reflection, and strategic adjustment. Results also suggest that in informal learning environments where teacher instruction is absent, vocabulary applications should be designed to provide pedagogically grounded feedback, scaffolded reflection, and peer-oriented confirmation to promote sustained engagement and effective form-meaning links.