Uyen Nu Thuy Nguyen
This study investigated the effects of AI-mediated speaking practice using a voice chatbot on Vietnamese EFL students’ speaking skills and explored their perceptions of the learning experience. A sequential explanatory mixed-methods design was adopted with 49 English-major undergraduates participating in a 15-week quasi-experimental intervention. The experimental group practiced speaking with an AI chatbot, whereas the comparison group received face-to-face instruction. Data were collected from pre- and post-speaking tests, questionnaires and semi-structured interviews. ANCOVA indicated that, after controlling for pre-test performance, the AI chatbot group achieved significantly higher overall speaking scores than the comparison group, particularly in fluency and coherence. Additionally, participants valued the chatbot’s authentic interaction, flexibility, and opportunities for regular speaking practice despite reporting occasional technical and interactional limitations. The findings support the pedagogical value of AI-mediated speaking practice in higher education.