The EN and JP communities on Atomos have played well together, literally and "play nicely children", since from the start. I've been in parties ranging from me being the only EN speaker to entirely EN players from Day 1. I'll argue that servers which start out multicultural/multilingual tend to develop their own multi-national/linguistic cultures. I never played XI so I can't speak to their regional server structure, but I'll guess it was a similar case in that game too.
I totally get why Japanese people would want to play only with other Japanese people; even though English is compulsory education, their general facility with the language is low. I understand Japanese to some degree and can speak it to a lesser degree, but don't ask me to read and type it fast enough to be able to communicate online. My wife's the same with English; her listening/speaking/reading are very good, but her typing speed is abysmal.
While I don't like the idea of being blacklisted simply for not being able to communicate in Japanese, I do realize that I rolled on a Japanese server and that it's my responsibility to play by their rules. In my case, this means keeping my head down, sticking to mostly FC groups, being polite when in PUGs, and not putting myself in situations where fast communication is key. Thankfully I'm a really casual player so none of these are problems for me.
