You’re right, they are indeed printed in English.
In this thread I posted pictures and all the information I know (which is next to nothing): www.elitefourum.com/t/this-is-a-fake-card-right/17482/18
Still looking for that Pikachu… 
PS: Although I’ve never seen them before, this Bulbapedia page mentions the Deck is also released in Danish and Swedish. Not sure how accurate this information is however, since it doesn’t mention Italian at all and I have seen some Italian VS cards in the past. I think @hazard24 showed them once (I could be mistaken).
Also, not sure what information you are looking for @mjisaacs , but here is some basic info for the scarcer languages among them:
- Chinese: Everything known can be found in this article that was made by @guangsta .
- Polish: Only Diamond & Pearl and Mysterious Treasures (and one Pikachu from the Pikachu World 2010 set) were released in Polish
- Russian: XY through XY BreakPOINT were released in Russian, including some blister and McDonald’s promos.
- Dutch: Base, Jungle, Fossil, and some promos were released in Dutch. But you already knew that.
French, German and Italian were released in almost all sets, although there are some exceptions (like no French Skyridge release, or no Italian Supreme Victors release). Spanish and Portuguese are released a bit less, and there was a period they didn’t include Reverse Holos in their sets (like Majestic Dawn and Stormfront for Spanish, or Next Destinies through the end of XY for Portuguese). Korean has their own sets, which are a mix of multiple Japanese sets usually.
Here I once started a list with languages per set. Still need to get back to it some time and finish it… You can also look at most of these Pokémon-specific checklists I created to get a good idea at what sets are released in which languages.
Greetz,
Quuador