I don't buy the language barrier argument. So what if there's little documentation in japanese, I don't see why these developers couldn't just learn the languages and frameworks by reading the documentation in english. Unless they don't speak english, and in that case, I'd say it's their own fault. I may come off as being arrogant now, but let's be honest here, english is the
lingua franca of our profession and any self-respecting developer will have at least a basic grasp of the language. You really don't need to speak a language perfectly to be able to read the documentation and learn some new technology. Also, english is quite easy to learn compared to other languages (much simpler grammar than most of the other languages I know or know about) and with all the US/Brittish shows, sitcoms and movies around you almost cannot help but to practice it regularly. Unless they synchronize them in your country, in which case you're out of luck there, but still...
Btw, if anyone is wondering, I am not a native english speaker. But I did learn how to program by reading the books and documentation that were available in english. If I had waited for somebody to translate these to my language, I probably wouldn't know a thing about programming to this day.