Acknowledging the critical role of working memory in language acquisition, this study examines the effects of multimodal input enhancement on working memory capacity (WMC) and collocation learning in adolescent and adult EFL learners. A cohort of 117 participants was randomly assigned to either experimental groups, receiving enhanced textual and auditory inputs, or control groups, experiencing standard inputs. Assessments included the Preliminary English Test, n-back test, and immediate and delayed collocation posttests. The results indicated that multimodal input significantly improved WMC and the recall and retention of collocations for all learners. Adolescents, in particular, excelled in both immediate and delayed tests and adapted their WMC more effectively in a multimodal context than adults. Additionally, an interaction between age and WMC was noted, affecting collocation recall and retention. These findings affirm the benefits of multimodal materials in enhancing cognitive functions and memory resources, thus improving language learning. The study offers practical insights for educational practices, advocating for the use of varied modalities in teaching materials to cater to different learning styles and cognitive needs. It also highlights the significance of designing age-appropriate materials and managing cognitive load in curriculum development, providing a tailored approach to language education for diverse learner populations.
