What to do with non-English questions or answers?

What should we do with questions (or answers) that are written in a non-English language?

I'm now talking about:

• Problem using any docks (Cairo, AWN, Docky)

These can be downvoted, but what if the question or answer is useful? It could be closed, should the reason be "too localized"? As a last resort, the question or answer could be flagged, especially for answers which can be "closed".