The Effectiveness of Task-Based Learning (TBL) in Enhancing Vocabulary Acquisition among ESL Learners: A Study in Phulu High School, Lao Cai, Vietnam.

The global demand for English proficiency has placed increasing emphasis on effective pedagogical strategies in ESL contexts. Vocabulary acquisition is a cornerstone of language learning, yet traditional, rote-memorization methods often fail to foster long-term retention or communicative competence, particularly in settings with limited exposure to authentic language use. This study investigates the effectiveness of Task-Based Learning (TBL) in enhancing vocabulary acquisition among English as a Second Language (ESL) learners at Phulu High School, Lao Cai, Vietnam. Sixty students were divided equally into an experimental group receiving TBL instruction and a control group taught through a traditional grammar-translation approach. Data were collected through pre- and post-vocabulary tests, classroom observations, and a student motivation survey. Statistical analysis using a paired-samples t-test revealed a significant improvement in the experimental group’s mean vocabulary score (45.2 → 72.6) compared with the control group (44.8 → 55.4), t(58) = 6.32, p < .001. Qualitative findings supported these results, indicating higher learner engagement, communicative competence, and autonomous vocabulary use. The study concludes that TBL is an effective pedagogical framework for improving vocabulary learning and communicative proficiency in Vietnamese secondary-school contexts. Pedagogical implications, including curriculum integration and task design recommendations, are discussed, highlighting the potential for TBL to enhance learner motivation and real-world language application. The study further contributes to ESL research by providing empirical evidence from a semi-rural, under-researched educational setting in northern Vietnam, offering practical insights for teachers, curriculum designers, and policymakers. Keywords: Task-Based Learning; Vocabulary Acquisition; ESL; Vietnam; Communicative Language Teaching; Secondary Education DOI: 10.7176/JEP/16-13-10 Publication date: December 30th 2025