Just imagine that you have some guys in same business meeting, and 2 of them speak in gibrish language. has you seen the scene in business meeting? No, It's just not polite.
For this we (who are english speaking) have to know is it
important or not :), but we do not know chinesse. In case
if there are lots of chinesse developers, it's much better
to make separate mailing list say chinesse-dev and keep non
english discussions there. Imagine if someone will start
postings in Russian or Farsi? or Arabian? or even Deutch?