Effects of a Task-Based Instructional Model on English Learning Outcomes of Non-English Majors in Vietnam

This study examines whether a structured four-phase task-based approach can improve English learning outcomes for non-English-major undergraduates in Vietnam and under what conditions it can be feasibly scaled in higher education. Addressing persistent grammar-focused, exam-driven classroom practices that limit meaningful interaction, the study aims to design, implement, and evaluate a needs-informed task-based instructional model (Warm-up, Task Introduction, Task Performance, and Task Evaluation) integrated into eight units across two general English courses. A two-phase mixed-methods design was employed. Phase 1 conducted a situational analysis using questionnaires (45 instructors; 450 students), semi-structured interviews (10 instructors; 15 students), and classroom observations to identify current practices and implementation constraints. Phase 2 implemented a 12-week quasi-experiment comparing two task-based intact classes (n = 60) with two comparison intact classes (n = 60), with shared content and assessments. Quantitative analyses (paired and independent t-tests) and qualitative thematic coding indicated statistically significant achievement gains for the task-based group and observable improvements in fluency and interactive competence. The study recommends targeted teacher development in task design and post-task feedback, alignment of assessment with communicative objectives, and institutional support (task banks, rubrics, and communities of practice) to sustain and scale task-based implementation.