There are plenty of Japanese scientists who are _at least_ extremely uncomfortable in English. Plenty of people who struggle to write their own stuff in English

There are plenty of Japanese scientists who are _at least_ extremely uncomfortable in English. Plenty of people who struggle to write their own stuff in English and get it corrected a lot. Though I think that beyond a certain level you have to be interacting internationally to get anywhere in your career so you're gonna be forced along. Plenty of people would learn Latin to consume some content, but doesn't mean they are proficient in it itself, would be another example. Having said that, I think that in the research field that merely ends up with "very confusingly written papers with mistakes large enough to hide process errors" more than "cannot communicate any info in English". But there are plenty of people who get their doctorate and their only English-language output is their final papers in themselves.