If I understand the gist of your position OP, it's that we should all learn one of these languages fluently enough to do academic research in those languages natively. Correct?
While I admire your personal determination and skill in learning Japanese, it's not something I myself can tackle in a big way. If I ever move there I'll just have to pick it up organically as I go, and I certainly won't be likely to manage skill high enough to study technical research in the language.
However, it's definitely true that men all over the world, particularly from the areas where the four languages you mention are spoken (whether multi-lingually or not). The drive of men to deal with the failures of most modern women is basically universal, as our welcome thread points out. So there's is plenty of room for connections and cross-pollination there, absolutely. This is a global phenomenon. That's a good thing.
From my angle of trying to actually implement something with robowaifu speech and languages, I'm somewhat interested in the generic characteristics of language itself. Kind of a meta-language-language if you will. Fortunately for me, there has been plenty of research done in English heh in this area, and I hope to apply some of it to my software development efforts. I realize my goals aren't quite the same as yours for multi-languages, but we can both agree that languages other than just English are important.