Toughest Puzzle - Who tells the truth?

This is labelled by www.ft.com as the toughest puzzle of all times. But it is not so difficult after all, as  I was able to solve it. Read the comments for my solution.

There are three guardians, A, B and C. Their ames are Knight, Knave and Chaos. Knight always speaks truly, Knave always lies. Chaos tossed a coin this morning to decide whether today he would behave like Knight or like Knave.
Your task is simple: ask three yes-no questions, each of a single guardian, and determine which is Knight, which is Knave, and which is Chaos. There is, alas, a complication: the guardians understand English but will answer in the local language, in which “Da” means yes and “Ja” means no. Or possibly “Ja” means yes and “Da” means no – you cannot remember.