Once again the pages of PPRuNe prove educational. I recently heard a C17 crew call for a return to OKBK and that they were "declaring an emergency". It genuinely didn't trigger any useful response until they stated that they had smoke in the cockpit. I had never heard the expression used over the r/t before that, in 29 years of flying around all sorts of interesting places.
However, when I declared a "PAN" while returning with one engine on my 135 at idle, I got the full treatment even though it was 3 in the morning. I certainly didn't mind the controller asking me to confirm it wasn't a practice, after he'd carried out all the correct initial actions.
Nick and Oogle, just because you do things one particular way in N America doesn't mean it's right. It's not just about ATC having the wit/language skills to question a pilot, it's a system-failure in your training that YOU and your countrymen are going to have to address. If you want correct results first time, use the internationally-agreed terminology. Perhaps a useful topic for a Flight Safety push Stateside sometime, particularly for crews who are likely to spend time working with non-USA ATC?