Bill Poser has a Language Log post on the curious fact that the identical (and delicious) roast-meat product is known in the U.S. as gyro(s) and in Canada as doner or donair (from the Turkish döner). It’s not a matter of respective numbers of immigrants nor of who runs most restaurants (Greeks prevailing in both, in both countries); Bill suggests that it’s “an example of a founder effect, that is, that it is essentially an accident, due to the language used by the first people to introduce and popularize the dish…. In the case of Canada, if doner was used first, if Greek restaurants introduced the dish out of awareness of its popularity in other restaurants, where it was called doner, they may have used doner rather than their own name in order to attract customers already familiar with the dish under its Turkish name.” That may well be the case, but an additional fact that Bill tosses in at the end may be important here: “Incidentally, the Greek term is actually derived from the Turkish. The earlier Greek term is reported to be ντονέρ [doner]. Greek γύρος ‘turning’ is a calque of a Turkish original that was first borrowed into Greek, then replaced after independence.” I’d like to know more about the history of this; if it was indeed replaced after independence (i.e., in the early 19th century), then it’s irrelevant here, but if it remained in common use (like many other Turkish-derived terms) until after the Greco-Turkish War of 1919-1922 it’s possible that the early Greek restaurateurs in Canada called the dish ντονέρ [doner] and naturally used the term in their menus. Like Bill, I’d love to hear from anyone who has more information.
Another point is the pronunciation of “gyro(s)” in English; I, like virtually everyone in NYC (including Greek restaurateurs), say [dʒaiɹow] (JYE-roe), but my brother (who’s spent his adult life in Southern California) uses the Grecizing pronunciation [jiɹow] (YEE-roe) and is horrified that I, a linguist and philhellene, use the “bastardized” form—so horrified that on a visit to New York (while I was still living there) he insisted I use the “correct” form when ordering. I obediently asked for two yeeroes; the counterman looked at me, puzzled, then said “Two jyeroes?” My brother gave up in disgust. It’s an interesting regional split (assuming, as I do, that my brother, as he says, reflects universal SoCal usage), and for this too I would welcome further information.