Profiles of media use purpose in informal digital learning of English and their association with vocabulary knowledge

Informal digital learning of English has potential for vocabulary development, and both the amount and quality of the experience are critical. Existing literature has primarily examined the association of the frequency of informal digital activities with L2 vocabulary development and has yielded inconsistent findings. The inconsistency might be due to viewing digital activities as homogenous entities without considering learners’ agentic and purposeful appropriation. This study aimed to elicit learners’ idiosyncratic media use purposes during informal digital activities, and examine the contributions of the frequency and media use purposes to receptive and productive vocabulary knowledge. Survey responses on informal digital English activities and vocabulary knowledge test were collected from 329 Chinese university EFL learners, supplemented with follow-up interview responses from 16 participants. K-medoids clustering, specifically the PAM algorithm, was used for cluster analysis, which revealed four profiles of media use purposes. Hierarchical Regression analyses showed that frequency and media use purposes contributed differently to receptive and productive vocabulary knowledge, with media use purposes mattering more for productive knowledge. Learners with balanced media use purposes performed better in productive vocabulary knowledge. The findings suggest adopting a relative lens when understanding the contribution of the quantity and quality of informal digital experiences to different aspects of vocabulary knowledge. The findings further support pedagogical initiatives that encourage students to expand and diversify their media use purposes, socialization purposes in particular, in informal digital learning of English.