Applying Cognitive Linguistics to Enhance Vietnamese English-Major Undergraduates’ Learning of English Modal Verbs

English modal verbs (EMV) have long been regarded as a challenge for English as a Foreign Language (EFL) learners, partly due to the widely used conventional speech act teaching method. The Cognitive Linguistics approach, which is believed to offer a more systematic explanation of English modals, has been introduced and applied to the teaching of English modal verbs in various international contexts. In this study, the researchers aim to investigate the perceptions and attitudes of Vietnamese EFL learners toward the application of Cognitive Linguistics at the tertiary education level, and whether this approach can improve their performance in using modal verbs through a Cognitive Linguistics intervention. To achieve the research objectives, two tests (pretest and post-test), questionnaires, and semi-structured interviews were conducted with 18 Vietnamese English-major undergraduates. Analyzed using SPSS 26, the research findings revealed a significant improvement in the students’ performance in using English modals following the intervention. Additionally, the participants reported that the systematic explanation of modal verbs enhanced their ability to distinguish between social and logical functions of EMV more effectively than traditional methods. Ultimately, this study provides valuable insights into the perception of modal verbs among Vietnamese EFL learners, with implications for English language teaching and curriculum design.