I think that is a common phrase/ question in every language: one sees that something is wrong (children are crying, people are waiting alongside the road, there is a huge queue, ...) and then one asks that question in order to get an explanation... Dutch: - wat scheelt er ? ('schelen' has the same root as 'verschil', difference, and refers to things being different from ... [the way they 'should' be]; therefore we say that some people are scheel, meaning that they are cross-eyed : one eye looks in a different direction than the other) - wat is er aan de hand? (lit.: what is at the hand? or something the like - but understood as: what is happening? ) What is your equivalent for that (and its origin if possible)?