This was an idea I came up with and shared with my $5+ backers on Patreon a couple months ago. If you would like to see such behind-the-scenes details, please consider supporting my Patreon page:

https://www.patreon.com/onpon4

Or, if you just want to support my libre game development efforts, you can do so via my Liberapay page (which is properly libre-friendly):

https://liberapay.com/onpon4

So what is Tangomon? Tangomon is an educational monster battling game, in the same sort of vain as Pokemon. It was designed with vocabulary in mind, but can be theoretically used for all kinds of learning. Your monsters, known as tangomon, attack with words, known as tangojis. When you have completely memorized a tangoji, you can convert it into a tangokan, which you can use to convince other tangomon to join your team. Your goal is simple: collect them all! Of course, I am personally a player, of course, which is why I developed it; I use Tangomon to study Japanese vocabulary and practice reading kanji.

A short video showing some Tangomon gameplay can be found here:

https://goblinrefuge.com/mediagoblin/u/onpon4/m/tangomon-gameplay/

And the game itself can be found here (currently source code only):

http://tangomon.nongnu.org