Abstract
This study investigates the impact of Mobile-Assisted Language Learning (MALL) on vocabulary acquisition among adult TESOL learners. Sixty intermediate-level learners were divided into an experimental group using a mobile vocabulary app and a control group engaging in traditional paper-based exercises over four weeks. Results showed that the experimental group significantly outperformed the control group in vocabulary retention, scoring 15% higher on post-tests. Additionally, learners using MALL reported higher motivation and engagement. The findings support cognitive theories such as spaced repetition and multimodal input, highlighting the pedagogical advantages of mobile technology in language learning. However, considerations regarding digital literacy and access to technology remain critical for equitable implementation. This study contributes to the growing evidence base supporting the integration of mobile technologies in TESOL and suggests directions for future research on long-term effects and broader language skills.