I've had the idea of making a fully localizable programming language for quite a while too, but like you, I've never actually done it due to the amount of maintenance a project like that would require.

My idea was to make it possible to transpile between all the language variants and allow machine translation of variable names and comments. That way, after a new language variant were implemented, users (primarily teachers) could take any compatible code in any language they even remotely understood and translate it, then do just a bit of cleanup and be able to contribute it back and use it when teaching.

Then I'd build a repository of these small programs, each with a set teaching goal in mind, translated into as many language variants as possible.

But now this is starting to sound like months and months of work, and since I can't focus on a single side-project for even a few weeks, is unfortunately never getting done...