Localization: The state of the nation?
This article is written a year ago. What do you think now about another languages?
EDIT: Especially not mixed, separate communitys for another languages
I'll give you my thoughts.
StackOverflow was a community of English speaking people at conception and is a community of English speaking people as of now. Sure, some of us speak other languages (I speak fairly good French, for example), but the community as a whole speaks English.
In order that every member of the community can understand each other and understand the cultural norms of said community (i.e. the FAQ), we need to be speaking the same language. If we have subdivided communities within a site speaking all different languages, how do moderators resolve difficult situations? How do I understand, for example, a Chinese question on x86-64 assembly? Pass it through Google translate? How do I answer it? How does anyone else know whether my poor Chinese is because I didn't understand the question or because I don't speak Chinese? Or do I just answer in English and then get downvoted by Chinese speakers for not using Chinese? More to the point, how do technical experts provide their expertise? You're limited to technical experts who speak that language which means you've just formed a different community. (*)
As an example in the real world, I'm British. A lot of British retire as expats on the Spanish coast with about a word or two of Spanish to their whole vocabulary. I consider that quite offensive. Holidaying is slightly different, but living and integrating with that community and not being able to speak the language? I think that's wrong.
So what I'm trying to say, bluntly, is that the community speaks English. If you want to participate, speak English. I wish we were all fluent in several languages and have personally tried to be, but the fact of the matter is that it just isn't possible. This is the way it is for now. Sorry.
However, and here's the really interesting thing, the Stackexchange/Area51 ethos is that anyone can form a community and if enough interest is generated / people are committed, it'll work. So, you can indeed form "Stackoverflow (in French)" if you so wish. The only thing you need is enough interested French speakers. I see nothing wrong with this and I'd happily hang around on a French speaking one if only to practise my French. I'm sure others would too, for their known languages. (%)
I do think we could do with a little more tolerance - not masses, just enough to be a little less hostile - to foreign speakers who make a decent effort at translation. Comments mocking people's spelling/grammar for example should be flagged into oblivion. Users should, ideally, try to correct minor grammar mistakes. However, there's a line to draw. Questions that are so badly written we can't make sense of them we can't answer. It's hard enough to communicate highly technical information accurately without the added barrier of not quite understanding a totally ambiguous sentence. That applies equally to non-native speakers and alleged native speakers.
I'd also say that the Stack Exchange network is very young for what it is. As per linked posts in your question and comments, the UI isn't internationalised yet. That's something that'll take time and resource and is only worth doing once foreign language communities become more prevalent. So there's going to be some delay before this becomes possible I expect. Be patient. Stack Exchange Inc are busy trying to tame an explosion. I imagine it'll happen in the end, just as foreign language communities for say programming will begin to form.
(*) I know the same argument might apply to programming languages. I disagree. Programming languages / APIs are by definition much, much simpler languages than human languages. Try doing anything in the NLP field and you'll soon realise this. It's easy for me to have a rough idea of what a programming language I don't know does. Not so with languages.
(%) There is an interesting debate to be had as to whether you have stackoverflowfrench.stackexchange.com or fr.stackoverflow.com. There would also need to be support for migration between foreign languages under the same topic where they are understood as the same topic.
English is the only language you can use to have a truly "planetary" resource. Sorry. I'd take best-effort bad English over having to Google Translate posts any day; when you weight the additional effort in writing your post with the much larger audience you're reaching I think enduring the effort is worth it.
(Also, what job position doesn't require knowledge of some English nowadays? Consider this as an excellent opportunity to improve your English beyond academic "just for the grades" levels)