I was working on this several months ago, but decided to completely restart and try again two weeks ago. Had a lot of business to take care of so could only do a few sessions of work.
Primary reason as to why I scrapped the first project was because I could not figure out a proper "green theming" and colors for the various Android screens. What it looks like on my computer can be totally different. I had the same issue with Fruity Game.
Basically, this is an open source Duolingo styled language learning app.
You can create courses/lessons for any language you want. This includes constructed or unofficially recognized languages.
The metadata repository comes from just the very basic idea of F-Droid.
Here are some examples of metadata:
"course": {"Form basic sentences": {"lessons": [{"challenges": [...]}]}, "Order in a cafe": {...}, "Speak about family": {...}
The README goes more in depth on how everything is structured.
Forgive me for lack of comments within the code. I wanted to get a quick prototype out to show a friend. I will make everything more readable soon enough.
The name probably makes no sense, but I could not find anything else.
NOTE: The app currently tries to detect your system language to only download courses from that, but there is only "en_US" available.