What the matter is vs. what is the matter used in the affirmative [duplicate]

Solution 1:

{something/nothing} the matter with {someone/something} is an idiom. It doesn't mean only that you have a problem, issue, or "matter";

It means either "what's WRONG with you?" in an often-condescending tone, or "what seems to be bothering you? if spoken in a more compassionate tone.

The way this idiom is phrased as a question is:

• What's the matter with [x]?

Even in an implied question, the pattern is the same: I wonder what's the matter with her.

In this latter construction, "what's the matter with her" becomes a NP and is the DO of "wonder". That is, [what's the matter with her] is taken as [that which is the matter with her]

But if you move the "is", as in your first example,

• I want to know what the matter is with her.

this breaks the pattern of the idiom, and risks being taken literally.

As for the third example:

• I want to know what's her problem

As WS2 hinted, "problem" is another matter altogether. To illustrate:

What's her problem?" is NOT equivalent to What's the problem with her? The first asks what she feels the problem is; the second asks why others think that she is causing a problem. And neither of these is equvalent to "What's the matter with her?

Thus, the third example is not a reasonable alternative to the first two (so let's stick to the matter at hand, and avoid problems.)

In conclusion, I'd say (notwithstanding what Oxford has to say about it) that the second example

• I wonder what's the matter with her.

  is the clear choice (at least in speech and reported speech). It is the most accurate, unambiguous way to say it.

Solution 2:

We may be getting confused here. Do I take it that everyone accepts John Lawler's dictum on what the matter is versus what's the matter? If so, let's forget that and concentrate on matter v problem, which incidentally are not synonyms.

Forget problem for a moment, think of matter. We use matter to ask of someone else, but we rarely use it for ourselves. We don't say:

The matter with me is that my leg hurts. We use a variety of other expressions, only one of which is problem.