Nobody seems to care one way or the other there, at least (I'm pretty sure my sale to Galaxy's Edge was UK English, for example). .
But, as you say, things are opening up as they should (Clarkesworld is doing translations of Chinese short stories, which is very cool). One of the reasons I read science fiction is to get blown away by new ideas, different world views, strange perspectives (probably why I'm a big Philip K dick fan. Man that guy was weird).
Stuff from different countries can often offer really different ways of thinking about things (I'm always surprised but the utterly bizarre Vietnamese short stories i read, for example)
This is absolutely what Science Fiction does for me, as well. (I'm pretty sure one of Dave's kicks mentions writing in exotic settings, because people want to be transported somewhere they've never been.)
Any recommendations on the Vietnamese short story front?