Add other languages doc.

[XinghaiGe]

Could we add other languages on doc?

[tim-schilling]

That's a great idea. Is this something you're willing to help with? Would you be able to lead this project?

[matthiask]

I worry a bit about keeping other language versions current, but that shouldn't stop anyone from contributing docs in additional languages. Maybe it would be useful to have other languages point to the english version as the most up-to-date version.

(I'm not a native english speaker either btw, it's a practical argument, not a normative one.)