I don't think English/ Australian "Oy!" has anything to do with Yiddish "Oi!" The meanings, AFAIK, are distinct.

> I am also interested in how this on-the-surface very offensive usage manages to survive and, to a degree, thrive. That is, it survives in spaces where something like "Jew post office" or "Black post office" could not.

But how "thriving" is it? I've never encountered it, and I used to take note of such things. At any rate, the word "Polish" in itself isn't considered offensive, as is "Jew" used in place of "Jewish." Presumably anybody imagining "black post office" would have not have used "black." So "Polish" gets some slack (as we Yanks say)that the other two do not.

> the most "American" word I use is "yo." I think the ladies kind of like it though.

So ladies don't say "Yo"? Why the self-imposed sexism, ladies?

Have Brits started using "yo" at the end of sentences yet? I began noticing it about a dozen years ago.