Actually, I think it has to do with how commonly a language is spoken and read. English is read and spoken as a mother tongue or learned language by some 1.5 billion people worldwide. Like it or not. This compares to perhaps 1.05 billion for Mandarin Chinese, 577 million for Hindi, 500 million for French , 500 million for Spanish, maybe 350 million for Arabic (?), 255 million for Russian, 170 million for German, and 5.7 million for Mongolian. (All figures per Wikipedia, so . . . ?) I once asked Bat why he didn't do a Mongolian version of his book, only one in English. His attitude was simple: It would be available to more people that way. He considered doing Russian and German editions (his other langauges), but felt the limited interest base wouldn't repay the effort. Rana Chhina and I considered doing a parallel Hindi edition of our now-finally-with-the-printer/binder book on post-independence Indian ODM, but realised that anyone with any interest in treading it would prefer to read it happier in English. Like it ot not, English is pretty much "the" global language and the core language of discourse in our international "hobby". I wish we were all more multi-lingual, but this is the shape of reality, I think.