What are you talking about?? Talking fast isn't an accent. Yanks don't have an accent anyway!
The southerners and hillbillies aren't considered Yanks! Call one a Yank and tell us about the reaction you get.
Anyway, the main subject here wasn't accents.
Among US pilots there are many many who have very poor RT. You'll never hear me defend them. The ATC's RT standard on the other hand is very good. Read the US AIM or the US AIP, the ICAO document which is exactly the copy of the AIM. Specifically Air Traffic Control tab, section 4-2-1 and on. Then see how often you can catch US ATC not speaking exactly as that. You will find a few but not often at all. Unless you've read that, you don't know what "Standard Phraseology" in the US is and you can't seriously critisize it. To be ICAO standard, a nation has to submit it's standards/procedures to the ICAO body so it's known to all. They don't have to copy CAA, JAA, CAD etc... standards to be ICAO compliant. They're not non-standard just because they don't do it the way you're comfortable with.
If you're flying in US airspace and are given this clearance "Bumble Jet 123, climb and maintain one five thousand" and you don't repeat exactly as that... YOU are the one who's NON-STANDARD. That using the word 'Altitude' which is your company's thing to do, is NOT standard in the US.
If you're unaware that when ATC issues a "traffic at xx o'clock" call during climb/descent/cruise whatever, and having seen the traffic you're unaware that now you're required to respond with "... traffic in sight", YOU are the one who's NON-STANDARD for not knowing the standards.
I find it amusing that some cathay pilots use the word Altitude with regards to altitude clearances with ATC (as company policy says), yet HK ATC doesn't use that format and doesn't use the word Altitude. Someone is NON-STANDARD here! Which one?? Does HK CAA even have the substantial documentation like the British or the US versions to cover it's acceptable RT? It's called 'Standard Phraseology' in the US by the way. They won't know what you're talking about if you say RT.