It always amused me that in Finnish you say "Butter Butter" for "Uh-oh". Silly Finns.
But then again... In German you say "egg egg" when you comfort a child after it got hurt. Silly Germans.
We Russians say "firs-sticks" when something bad happens. Silly us.
voi voi, or voi ei.... ughhh
Voi voi is equally used as oh dear!!!!! However it seems many of the accepted answers are actually ripped straight from Google translate. This is very disconcerting