We present a scalable, dialog-based conversational practice tool for English language learners that is operationally deployed on the TOEFL® MOOC. The tool consists of three applications of varying duration that recognize the learner's speech input and responds appropriately. Learners are also provided with basic feedback regarding task performance once complete. We envision this as the first milestone towards the proliferation of many such scalable dialog applications that can help language learners practice, assess and improve their spoken conversation skills.