Abstract

Although vocabulary acquisition is one of the primary building blocks of learning a second language, the sociocultural aspects of mobile-assisted vocabulary learning (MAVL) are still understudied, especially in multicultural contexts. While previous inquiries have scrutinized the affordances of learning technologies, the construction of learner agency—and the role of peer hegemony, empirical attention to their combined contribution to situated productive vocabulary growth, framed by specific cultural and institutional ecologies—remains scant. This research focuses these gaps on Malaysian and mainland Chinese university students through Vygotsky’s Sociocultural Theory. With the convergent parallel mixed-methods framework, quantitative data were collected through validated questionnaires and a productive vocabulary test (n = 480), while qualitative data were acquired through semi-structured interviews. Structural equation modeling showed that learner agency (β = .46, p < .001) and peer mediation (β = .35, p < .001) operates within macro-level structural constraints like exam pressure, curriculum design, and digital infrastructure as strong mediators influencing vocabulary production. Thematic analysis provided additional emphasis toward the internalization of vocabulary strategies dedicated to mobile devices and peer scaffolding frameworks. Malaysian students outperformed their mainland counterparts in engagement as well as in vocabulary gain, such learners exhibited enhanced lexical autonomy and heightened investment in peer-driven linguistic labor. A theoretical novel is the formulation of Cultural Mediation Sensitivity (CMS), which captures the adaptive and sensitive behavioral changes learners exhibit in relation to the expectations of their culture. This study offers a context-sensitive model of MAVL, adding new implications for educational design and policy in multilingual contexts.