This session introduces MiMi Chat, a Gen AI-powered tutor that serves as a conversation partner and provider of formative feedback and assessment, tightly integrated with classroom-based English language curricula. Now used at over 50 universities worldwide, MiMi gives students structured opportunities to practice speaking and receive real-time feedback aligned with CEFR “CAN-DO” goals—outside scheduled class time but directly connected to in-class instruction. Drawing on data from over 15,000 students, we examine measurable gains in speaking output and learner confidence. Case studies include use in a TED-based discussion course, a presentation course, a nursing communication module, and a cross-cultural communication program. We also share engagement metrics, feedback accuracy, and qualitative learner insights.