Mobile-assisted language learning (MALL) is reported to be beneficial for improving English as a foreign language (EFL) learners’ language learning skills. Although some studies have concen- trated on utilising a MALL application’s (app) affordances for improving EFL learners’ overall speaking performance, there is as yet little empirical evidence of its effectiveness in terms of developing EFL learners’ speaking skills and motivation-relevant factors. To tackle this knowl- edge gap, the current study adopted a sequential explanatory mixed-methods approach to explore the utilisation of a MALL app’s affordances for developing EFL learners’ speaking skills (including fluency and coherence, lexicon, grammatical range and accuracy, and pronunciation), foreign language enjoyment (FLE), and language-specific grit (LSG). With this aim in mind, we used blocked randomisation applying computer-generated random numbers to equally distribute 66 EFL learners across two groups. Corroborating the adequacy of the sample size via power analysis, the two groups were randomly assigned to a MALL group (33 EFL learners) and a face-to-face group (33 EFL learners). The MALL learners had interactive speaking activities inside the class and utilised the MALL app for their out-of-class interactive speaking activities. On the other hand, the face-to-face learners had interactive speaking activities both inside the class and in a language learning laboratory in addition to the class time serving as supplementary interactive speaking activities. An IELTS speaking test, an FLE scale, and an LSG scale were used to collect the required quantitative data, and an individual semi-structured interview was conducted to gather the qualitative data. Running one-way ANCOVA to analyse the quantitative data, the findings indi- cated that both MALL and face-to-face instruction developed the EFL learners’ overall speaking performance, speaking skills, FLE, and LSG; however, the MALL learners outperformed their face- to-face counterparts on all measures. Furthermore, the qualitative analysis uncovered several themes and categories addressing the MALL learners’ positive and negative attitudes towards and perceptions of the utilisation of the MALL app’s affordances, which could explain the quantitative findings. The findings are useful for EFL learners and instructors interested in utilising MALL apps’ affordances in their interactive speaking courses.
