This is a phrase I've heard many people use, and it sounds wrong to me; e.g.:
The thing about that is, is that she might take it the wrong way.
It seems to treat "The thing [...] is"—the entire phrase—as the subject of the sentence. Of course, even if that were allowed, the comma placement would still be questionable.
I'm curious to know:
- Is there a name for this wording?
- Is it specific to a certain dialect?
- Is its etymology known?