Actually, I don't even know if there are such things in German or French or other languages - which all seem more prone to diacritical marks, which I would imagine increases the difficulty of both construction and solution.
I was doing the Sunday New York Times crossword yesterday, and for some reason happened to think of a friend of mine from Chile whose grasp of English is excellent but for whom the occasional turn of phrase remains a mystery. Yet so much of crossword clues rely on familiarity with just those sorts of idiom, that it occurred to me to wonder how she would do with the NYT crossword; or how I would do with one from the Santiago La Nación, should such a thing exist.