In Dutch, vader means father.
I've thought about taking up Dutch for a number of reasons, though it will have to wait for my Japanese to get up to where I want it. I have to say, though, it would be strange asking about someone's "vader." I don't think I would ever shake the Star Wars imprint on that word.
On the other hand, the Dutch had a big clue as to the identity of Luke's father. Imagine the chuckles that brought when it was revealed, all the Dutch saying "Silly Americans, we could have told you ..."