CNN's Web page has a video segment from The Situation Room that describes the
serious problems with international pilots who cannot speak English well
enough to communicate with air traffic control. They provide a recording of
communications with Air China flight 981 in April in which the pilot has no
idea what the controller is saying and the controller's frustration continues
to build as his instructions are not followed. (This same recording has been
circulating in aviation forums for months.) Air China says that it was the
controller's fault for not speaking "standard" English, but the recording
makes it clear that the pilots simply couldn't speak or understand at all.

Several Chinese pilots and officials are interviewed; all are provided with
subtitles (even though they are nominally speaking English) because their
English is unintelligible. One pilot who supposedly passed an English test
that will soon become mandatory is asked if he has ever had problems, and his
response, in extremely broken English, is also unintelligible. And he's one
of the pilots who passed?

It's a rather alarming report. Controllers have known about the problem for
years but nothing has ever been done.