For the last 10 years, our learners have provided us a trove of data (over 1 billion learning events) on how they learn English. We use this data to create a "Machine Learning Loop" that incorporates annotated feedback from a team of over 600 trained professional English teachers. The Machine Learning Loop means that our IntelliSpeech^SM self-study platform learns from the feedback teachers provide and, at the same time, teachers learn from the feedback IntelliSpeech^SM provides.