People are increasingly aware that metacognition can help us solve problems more effectively. Scholars believe that students' metacognition can be facilitated by promoting the interplay between the unlimited long work memory for holding schemas and limited work memory for processing ongoing activities. In this study, a workshop designed teacher mediation method between English language teachers and students is implemented that focuses on instructional talk supported by a visualized thinking framework in learning English grammar. Consequent to student's automation from retrieving schemas to engage in the self-regulatory process of English grammar problem-solving, this section involves three English language teachers and students in their taught classes in a secondary school in China. The teachers were equipped with an explicit approach to teacher mediation through researcher-designed workshops. As the teacher mediation approach was implemented in English language classrooms, the researchers made meaning of their experiences through the dialogue and interaction between teachers and students by revealing the essence in the mediation process: dialogic assessment, cognitive scheme construction, automated schema retrieval, and metacognitive schema construction. Through teachers' English pedagogical grammar practice in the three example cases, metacognitive teachers and learners are expected to be cultivated in an interdisciplinary view.