In which varieties of English is it common to front predicates as in the following sentence?
Bought a nice house, he did.
In which pragmatic contexts is this done in these varieties?
In which varieties of English is it common to front predicates as in the following sentence?
Bought a nice house, he did.
In which pragmatic contexts is this done in these varieties?
All the varieties I know. I don't think it's regional, or varietal; it's just conversational, a sort of syntactic equivalent of Fast Speech Rules.
I suspect it's just an afterthought tag for Conversationally Deleted sentences like the ones Thrasher treats in his dissertation (Thrasher, Randolph H. Jr. 1974. Shouldn't Ignore These Strings: A Study of Conversational Deletion, Ph.D. Dissertation, University of Michigan, Ann Arbor). I posted about it on Linguist List here, here, and here.
That is, "Bought a nice house" is derivable, in context, from "He bought a nice house" by Conversational Deletion, and — in some cases, and if the speaker wishes — may be clarified at the end with a tag, whence the Do-Support.
Some other examples, derived from examples in Thrasher:
This doesn't work in every case of Conversational Deletion, since not every deleted initial sequence can form an appropriate tag:
It's fairly common in Welsh English, particularly in the South. Usually done for emphasis such as "Fed up, I am". You can find more about it in The Cambridge Encyclopedia of the English Language