Most of my working career was spent at a USA Fortune 500 company in the computer peripherals business. I was a manager in the R&D&M departments for 20 years. We had foreign scientists (all PhD's earned at American universities) who had immigrated from the UK, India, Germany, Czechoslovakia, China, Argentina and Israel in my various groups over my career. What I observed is that promotion to management levels above the small group depended crucially on English language skills. If a brilliant scientist or engineer couldn't make a cogent presentation to non-technical managers of my company, i.e the sales, marketing and finance people, then they did not advance above the first or second level of management. Indian origin scientists had good English skill, as did, of course the UK scientists. One of my best friends and a very brilliant scientist was from Czechoslovakia. His English accent was so thick that many senior executives could not understand him. I was able to promote him up to a level below myself as I rose in the company to a Chief Engineer position. However, if it had not been for my personal confidence in his technical ability, and my help to him in organizing verbal presentations to non-technical management, he would have been stymied. I think a lot of Chinese origin technical people are hampered in USA corporations by their difficulty with spoken English.