Show HN: I built a small app for FSI German Course (detawk.com)

DeTawk is a German-learning app in beta that builds its entire curriculum on the US Foreign Service Institute’s FSI German course. It aims to teach learners to speak by using native audio, dialogue-based drills, and FSI-style substitution/variation exercises, with Unit 1 available free and the rest added over time for a €5/month subscription. The post also explains the specific learning sections used in the course and how FSI estimates study time to reach B2/C1 levels.