This is pretty good and generally intense as a mental workout. Not too dissimilar to Duolingo, but it doesn’t have any visual portions for looking at or reading words. Perhaps in conjunction with Duolingo it would be a good speed course?
This particular post also makes me want to have a “study post” type/kind on my website. I’ve generally not been tracking it directly for things that aren’t otherwise reading, but it could include writing, listening, speaking, or otherwise working on educational related things that one might want to track: i.e. “how much time did I spend studying subject x?”
A study post is a kind of post that can indicate one or more activities involved in the learning process.