The Effect of Task-Based Learning on Grammar Competence and Student Engagement among Grade 11 Students: A Case Study at Phong Phu High School in Ho Chi Minh City

Abstract

This study investigates the effect of Task-Based Learning (TBL) on Grade 11 students’ grammar competence and engagement at Phong Phu High School in Ho Chi Minh City. Grounded in Communicative Language Teaching (CLT), this study employed a quantitative quasi-experimental design supplemented by questionnaire and structured classroom observation data. The quasi-experimental component involved two intact classes: an experimental group (n = 34) receiving task-based grammar instruction and a control group (n = 36) receiving conventional, textbook-based instruction. Grammar competence was assessed through pre- and post-tests, while students’ perceptions and engagement were examined through a six-item effectiveness scale, a six-item engagement scale, and eight-week classroom observations. Because the test scores were non-normally distributed, Mann–Whitney U and Wilcoxon signed-rank tests were used. The groups were comparable at pre-test (U = 480.50, Z = −1.558, p = 0.119). Although both groups showed significant improvement from pre-test to post-test, the experimental group demonstrated significantly greater gains[cite: 9]. A Mann–Whitney U test of individual change scores (post-test – pre-test) revealed a significantly larger median gain for the experimental group (Md = 0.70, IQR = 0.48) than for the control group (Md = 0.30, IQR = 0.20), U = 114.50, Z = −5.89, p < 0.001, with a large effect size (r = 0.70)[cite: 9]. These findings indicate that task-based grammar instruction was associated with greater improvement in students’ grammar performance than conventional instruction[cite: 9]. Questionnaire results showed highly positive perceptions of TBL, while data from classroom observations descriptively indicated positive trends in participation, collaboration, attention, and confidence[cite: 9]. These preliminary findings suggest that TBL can serve as a supportive, learner-centred approach to grammar instruction in Vietnamese upper-secondary EFL classrooms[cite: 9].