I’m basically going to repost here an entry from No-sword, because it’s an interesting question that I’m completely incompetent to answer, and I thought perhaps some of my more theoretically inclined readers might have some interesting comments:
Japanese is considered to have SOV word order and topic-comment sentence structure. So one uncontroversial way for a man to casually say, for example, “I don’t understand English” is
ore wa eigo ga wakaranai
I (topic) English (subject) be-understood-NOT
“As for me, English is not understood”
= “I don’t understand English”
But in spoken Japanese, it’s very common to hear something like this (note that the particles (wa and ga) have been dropped and wakaranai slurs into wakannai; these are uncontroversial changes):
eigo wakannai, ore
English be-understood-NOT, I
The interesting thing about this sentence is the pronoun tacked on the end. This is unique to spoken Japanese (although of course you see it in some written Japanese that closely mimics spoken Japanese). The opinion in most official grammars is that nothing is supposed to come after a sentence’s main verb except for particles, like yo for emphasis or ka for interrogation.
So my first question is, do we interpret this as an 俺、英語分かんない in which the comment (英語分かんない) has been emphasised by moving it up to before the topic (俺)? “Comment-fronting”?
Or is it considered a pro-dropped 英語分かんない (a well-formed sentence if you overlook the missing が) to which a specification of the topic (俺) has been attached as an afterthought?
Or does it depend on context? Or is it something entirely different? Or impossible to determine?
Like Diane in Matt’s comment thread, I immediately thought of the colloquial French construction “J’sais pas, moi,” but in that case the pronoun is left in its normal position but repeated for emphasis at the end, an easier deviation to explain.