For sets I’ve created this thread: Sets and Languages: Overview list.
That’s unfortunately a bit trickier, since WotC era promos are some of the hardest to find cards in foreign languages. I for example collect Pikachu in all languages, and have yet to find the German and Spanish Flying/Surfing Pikachu promos (for German the Flug-Pikachu variant, not the common Fliegendes Pikachu), which I’ve only seen twice each in ~8 years time. And I know a few other single Pokémon collectors who are also missing just some of the foreign WotC era promos.
But if you want to know which languages a specific WotC era promo was released in, I can see what I could find. 
Greetz,
Quuador