The Effects of Immersive Virtual Reality on Language Learning: Causal Effects on CEFR-Aligned Grammatical and Lexical Performance and Within-VR Comparative Effects on Communication and Intercultural Competence

This randomized controlled trial tested the effects of immersive Virtual Reality (VR) enhanced with artificial intelligence on English language development, operationalized as performance on an author-developed, CEFR-aligned language proficiency battery emphasizing grammatical and lexical performance, in undergraduate Chinese EFL learners (N = 477). Participants were assigned to NLP-enhanced VR, ML-enhanced VR, SA-enhanced VR, or a traditional instruction control condition. Posttest scores on an author-developed, CEFR-aligned proficiency measure were analyzed using mixed-effects ANCOVA to account for recurring laboratory sections. The NLP-enhanced VR condition yielded substantially greater grammatical and lexical gains than all other conditions (F(3,473) = 1139.45, p < .001, η 2 = .88), with post hoc tests confirming its superiority. Communication competence and intercultural competence were measured only within the three VR arms. No reliable between-arm differences were detected for communication competence (F(2,354) = 0.02, p = .982) or intercultural competence (F(2,354) = 1.06, p = .349), so no causal claims are made versus the control group for these outcomes. Findings indicate that context-sensitive, NLP-driven conversational support in immersive VR can causally enhance foundational linguistic subsystems—vocabulary, grammar, and sentence-level syntax—as measured by the CEFR-aligned assessment, while the durability and communicative transfer of these gains require verification through delayed and independent measures.