Hello, my name is Peter, I am learning Czech and creating a service for that in F#: https://check-your-czech.azurewebsites.net. In the talk, I will describe its motivation, story and related development adventures.
In short, Duolingo and other apps available for Czech help with training vocabulary and speaking ASAP. They don't help much with speaking correctly though and I don't want to sound like a child all my life.
I realized that and my developer's soul commanded to create something to help me. Having C# background, after attending all the FSharping meetups, I decided to try the SAFE stack.
Check Your Czech is supposed to selectively train Czech grammar rules. There are five exercises now, the project is open source under active development: https://github.com/psfinaki/CheckYourCzech