In my little town in China we have a lot of German engineers, managers, and mechanics that work in partnership with the Chinese. The medium language of communication is English. I talk to these engineers often. They tell that they can't just leave the production of anything to the Chinese because they are going to screw up the product. It is not that they are not smart or incapabale, but when they start cutting corners they get an inferior product. The Germans do not have time to learn Chinese, and if Chinese people think English is hard- German is a lot harder. So the language of communication has to be English.
One mechanic tells me that he makes precision parts for high tech equipment. The cuts and holes in the materials have to be precise because a certain part is connected to something else. He says that some Chinese managers want to save some money by making the cuts, holes, etc. in a different way. That is the problem, and I believe that for now China will still keep needing foreign experts for many jobs- most will speak English.