Thank you for sharing this. My girlfriend is fluent in Korean, I was when I lived there for a year while in 2nd grade, and I've been trying to learn Korean again. I'll definitely be checking out your app!
Please do! It has some growing pains. While it supports 100+ languages, Korean is one of few that has first-class support (just based on cross-cultural relationship statistics). I may reach out to you over email if you sign up.