I was fortunate (?) to have worked at one of the colleges that train foreign students, so over the time I was there I came to understand what they were saying.
The key here is that what these kids say on the radio isn't necessarily what they mean, regardless of whether the pilots have done "Aviation English". A lot of the meaning gets lost in the translation, and doesn't necessarily make sense to those who don't work in the environment every day.
I wish I had a dollar for everytime I had to translate for my Captain back when there were students from non-English speaking backgrounds around the Tamworth-Narrabri-Moree-Armidale areas. You can't blame the individual cadets. It's the system that permits them to operate with the minimum level of English that is the problem.
However, we need to look at the problem from both sides of the coin. Hands up those who find 3 or 4 or 5 instructions in one transmission from ATC confusing???
I'm first to put my hand up. Yet we have to deal with this every day.
Or, think what it would be like to go to China and have to learn to fly in Mandarin......