Crisis-driven vocabulary in an immersion context: International students’ learning strategies and COVID-19 lexical knowledge during the 2020 pandemic

The COVID-19 pandemic rapidly expanded the vocabulary encountered by international students in English-dominant environments. This descriptive-exploratory study examines vocabulary learning strategies and COVID-19 lexical knowledge among 69 international students at an Australian university during September–November 2020. Participants completed a 35-item strategy questionnaire and a 31-item vocabulary test. Under the study's retrospective category mapping, determination strategies had the highest mean (3.34), followed by cognitive (3.21), memory (2.92), metacognitive (2.82) and social strategies (2.63). Listening to pronunciation and engaging with English media were the highest-ranked individual strategies. Category boundaries overlap, so item-level behaviours also inform interpretation. The Internet (43.5%) and social media (26.1%) were the primary reported vocabulary sources. Mean tested knowledge was 61.5% (SD = 16.5 percentage points across items), with an item-level awareness–knowledge correlation of rho = 0.644 (nominal p < .001). Knowledge exceeded reported awareness for 15 items, a pattern compatible with compositional inference, unremembered exposure, guessing and distractor effects. The recovered survey archive supports the analyses, but the vocabulary key was reconstructed and author-checked rather than recovered as an original key. These historically bounded patterns suggest questions about learner-controlled and socially mediated strategies during disrupted immersion. Because interactional opportunity and self-regulation were not directly measured, the study cannot distinguish environmental from self-regulatory explanations. Selection, measurement and sampling uncertainty limit generalisation; confirmatory research under uncompromised immersion conditions is needed.