Here’s a comment from Rob about this back in May in reference to the React docs.
Here’s what reactjs.org does:
Once you say that you want to own a translation they create a new repo with a complete copy of the site and keep it self contained. Changing languages on the site means you go to a separate subdomain, which serves the contents of that repo.
I’m not sure at what point the new translated version of the site is considered complete enough that it can go live? And I can’t imagine what’s involved in updating all translated sites every time a PR is merged in the english version.