Vocabulary learning that overlooks the discrimination of single sounds in English language learning could lead to communication difficulties, such as the inability to hear and speak English pronunciation. To address this issue, vocalization strategy, in which students listen to the sounds of words and memorize them aloud, is considered a useful learning strategy, and has been reported to influence performance in English language learning. Many studies have shown that metacognition promotes the use of this strategy. In this study, we developed an English vocabulary learning support system using dictation-type speech recognition technology and evaluated whether it activates learners' metacognition and promotes the use of vocalization strategies.