Levels of English

Reading a recent post by Michael Leddy (http://mleddy.blogspot.fr/2015/10/os-x-el-capitan.html), I was reminded once again of my time as a teacher of English as a Foreign Language. Michael was obviously moving in far more exalted and interesting circles than I was. My job, after all, was simply to help my adult students to "get by" in their business and/or tourist dealings with English-speaking people, to function at a fairly basic and boring operational level. What time is Herr Grüber's flight arriving from Zurich? Please direct me to the Conservative Party Conference.

But the funny thing was that my students were far more interested in the subtleties of the English language than in spelling their name. They (and I) gratefully seized upon any opportunity to get away from the soul-destroying "functions of English" and to concentrate instead on language learning as an intellectual exercise. For example, what exactly is the difference between "I have lost my keys" and "I lost my keys"? Or again, how do question tags work? In terms of communicating in a foreign environment, neither of these topics is of the slightest use but we, teacher and student alike, loved them!

Incidentally, do question tags feature as prominently in American English as they do in British English? In the States, they just say "right", right? Right.