Due to better accessibility and practicability than other technological devices, mobile devices have been recognized as a delivery channel with great potential for more effective language learning. Mobile-Assisted Language Learning (MALL) enjoys the advantage of mobility, which enables seamless learning from inside to outside the classroom. The present longitudinal study aimed at investigating the effects of a MALL-based vocabulary intervention on the language learning outcomes of a group of EFL learners. In so doing, a sample of 139 students were recruited as the participants of experiment in which various mobile applications – e-dictionaries, word lists, various vocabulary learning applications, and Microsoft Student with Encarta Premium – were employed for MALL intervention program. The experiment lasted for a period of one year during which the participants were exposed to 8 various vocabulary tests in different intervals. For the purpose of the present study, two waves of the collected data were statistically taken into account to investigate the pattern of change in vocabulary knowledge. The findings of the latent growth modelling analysis revealed a pattern of significantly increasing vocabulary knowledge over time. Overall, the results of the data analysis confirmed the positive effect of MALL-based intervention program on learners’ vocabulary knowledge. Finally, the theoretical and practical implications of this study are discussed.
