We here in the States do have the advantage that the language of aviation (English) is also the mother tongue of both pilots and controllers, over a very wide region. Including our buddies to the North.
So either "Emergency" or "Mayday x 3" will be equally understood, immediately.
Of course, the same is true in Oz - but you have tighter ties to old Blighty, (where "the proper thing is always done"), and a little higher probability of working with overseas controllers on relatively short legs.
I sure understand why a rigorous consistency in phrasing is needed when you have Turks talking to Dutch in English (or any other combination you can dream up).
Then there is the "Right Stuff" factor, where "Mayday, Mayday, Mayday!" just seems like making too big a fuss. Half your spacecraft explodes, and the call is, "Houston, uhh, we've had a problem."
"Cool and calm" is the cultural attitude - and we can get away with it (see paragraph 1).