"Which programming languages support closures?" seems pretty straight forward and focussed?
That is, there is a clear question, a reference to what closures are (so there cannot be confusion), and a request for a fairly clear-cut answer.
Selecting the right language to develop an application in is incredibly important. Certain things are easily achieved in programming languages with closures that are not as elegantly/easily achieved in languages without.
It's therefore a consideration in the process of planning which programming language a software tool, library or application will be written in.
How is this question in need of "more focus"?