AI Teacher project aims to explore how we can utilize language technology (e.g., natural language processing) for language learning. The AI Teacher is an innovative online language learning tool for learners of Japanese (especially, for beginning~intermediate levels). The AI Teacher is "interactive" in that it can catch user’s mistake(s) automatically and give the user real-time feedback as s/he types a sentence. The grammar knowledge of the AI Teacher is crowdsourced from Japanese language teachers, and in this resepct, the project bridges the fields of Japanese language teachers and language technology. This is a collaboration with Dr. Tetsuro Takahashi (from Fujitsu Lab.), and the project was funded by the generous grant support of the Japanese Foundation, Los Angeles.