JMST is post-BB GMS

God, translations into english are not because GMS has the most content. It's because structures for all languages are easier to be translated when english to that language, and since english is the universal language.
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Also, BB always meant Big Bang, it's the most obvious abreviation used here and even by maples. Although BB may mean Blaze Break, who refers to Core Blaze's quest, only a JMS player might understand that. It's not common sense, it's acquired knowledge through a little gameplay on JMS until you find that out from megaphones.

I've never played any other version besides JMS; when I see BB, I think that giant immobile punching back that gives billions of exp. JMS players are having trouble how to abrreviate "Big Bang"

English doesn't have the same structure as Japanese (it does with Chinese and German). It is, like you said, a universal language and more people speak it than Korean.