Instead of entire new programming languages, maybe existing languages can have alternate localizations (done at the IDE level). The same source code would display in a different language from a user with their IDE in Spanish vs the user with their IDE in English.
Edit: Food for thought regarding reserved keywords...
I am with you with the relative movements. Most of the faster songs are fun because they have triplets or alternating patterns that are easy to adapt to once you're used to the pattern.
As for the game you played, it must have been the DDR series. You can't "finish" Stepmania since it's an open source rhythm game where the community has created thousands and thousands of songs to to play.
It's hard to explain, but with these sort of games your brain "feels" if something is off (a little bit of latency, etc). I get a similar feeling playing instruments. It's quick to adapt to these changes, but the feeling of something being "different" still lingers for a bit.
Used to play (still could if I got back to it) at that difficulty with my keyboard. Got to the point where I could have conversations while playing. I also play guitar so I stopped playing Stepmania to avoid extra strain.