Historically, the worlds championships decks have only been printed in English, but @queendrifloon pointed out to me the recent decks have also been printed in a couple other languages. It appears to have started in 2022, which makes sense since that was the big comeback of championships decks for various reasons.
We confirmed French and Italian decks, so is anyone aware of any other languages? I would suspect German at a minimum; Spanish and Portuguese less likely but possible.