One might say English is the javascript of the spoken language.. perhaps we can come up with some framework that makes more sense and will translate down to english so we don't have to deal with it directly anymore!
It's really interesting to look at history and take in how English became the world language. Spanish, French and German all looked like they'd come out on top at some point, but they all lost a lot of relevance after Europe was shattered in ww2.
And now we have once again two competing languages dominating the world stage, american English in the west and Chinese (or Mandarin I guess) in the east.
I can't imagine a future when these merge naturally, because they don't have any common ground to speak of.
However, realistically speaking... If we actually do manage to become a singular community, one language would win at some point. I doubt it'll happen while we're alive, but it'll surely be an interesting topic for historians of the future... As long as we survive long enough I guess
English itself has already been heavily influence from its neighboring languages (something like 30% of words have french origin), if there are useful words in Mandarin it's taken quite a few of them as well (recently learned that 'saving face' is a very literal translation).
As far as merging, Mandarin borrows phonetically sometimes but isn't nearly as eager as Japanese, which has found quite a bit of loanword usage. Which is to say, I think it's possible.