subordinate clauses

[beachboy]

Which one is right?:
I don´t know what the problem with her brother is.
I don´t know what´s the problem with her brother.
Is it the kind of mistake that even Americans make?

[cclaff]

Which one is right?:
I don´t know what the problem with her brother is.
I don´t know what´s the problem with her brother.
Is it the kind of mistake that even Americans make?

Either way is acceptable, but I personally prefer the second one.

[beachboy]

I see!!! But what is the explanation for this? Has it got to do with identifying what the subject is?

[susiedqq]

I see and hear it:

I don't know what the problem is with her brother.

[riverkid]

Which one is right?:
I don´t know what the problem with her brother is.
I don´t know what's the problem with her brother.
Is it the kind of mistake that even Americans make?

Because these type of statements are not really question forms, the normal neutral doesn't employ a question word order - "What is the problem ...".

But since speech often makes use of changed word order to change the nuance or the feelings expressed, often the question form is maintained.