Although I guess you would know but I thought English is the language used in all air flight.
In China and Russian airspace, only foreign pilots are spoken to in English. Pain in the butt listening to several languages on frequency.
But the point is, while all pilots / controllers are required to meet and speak a certain level of english, many many pilots flying do not meet that level. For many retesting is required i believe every two years?? Not sure
And even for those who meet that level, their understanding of proper verbs and adjectives can be found wanting specially when under duress. I have to remind myself on a regular basis, that the receiver of my communication most likely did not get the full understanding of my message, even when they appear to speak "perfect" english.
And now we see that the report of communication with this plane is probably false. Which makes sense, because company rules require that no employee talk to the media in the immediate aftermath of a crash or incident. This pilot would/could be in trouble with company