英語ディベート経験が日本人英語学習者のスピーキング能力へ与える影響 : L2ワーキングメモリに着目して

This study examined whether experience in English impromptu debating enhances speaking proficiency and how second-language (L2) working memory (WM) contributes to this improvement. Participants with and without debate experience were compared on speaking complexity, accuracy, fluency (CAF), and conversational reaction time (RT). General English ability, motivation for English learning, and extraversion were controlled between the groups. The debate group showed significantly higher complexity and fluency, as well as shorter RTs, while no group difference emerged for accuracy. A significant interaction between group and WM was found exclusively for complexity and fluency: higher WM predicted better performance only in the debate group. The debate group also demonstrated higher L2 WM, and the length of debate experience marginally predicted WM, suggesting that debate practice may strengthen L2 WM, which in turn supports more complex and fluent speech. These findings indicate that English debating, requiring rapid logical analysis and role-taking, places high cognitive demands on L2 WM and can effectively promote speaking development.