I find this forum already much softer and much more welcoming than any other internet forum I had been to. Here the differences vanish, undergrad, grad student, postdoc and senior professor all can speak out. It is so liberating. Where else can a grad student or undergrad can have a war of words with a prof? That itself is a big deal.

Edit: I do understand your concern of people leaving put off by the reception. When I observed one such instance here, I did try to put in my 5 cents for urging the concerned person to stay.

This kind of hostility to newcomers is common in all internet forums. Once I was not doing mathematics and had been part of another internet forum for a particular trend of software, and every newcomer had to go through a "hazing". I was not much taken aback here due to my past experience. The stack overflow software reduces such social cliques and politics and hazing. Still it will be there to some extent. This can't be helped. It is not the fault of the existing people or the creators. Blame human nature.

Maybe we are paying a tribute to the Paris or France which was home to Grothendick and Serre, by being forced to read French.

It seems like everybody with more experience than me says that my concerns are unfounded, which is reassuring. I'm happy to not do anything about non-English posts so long as posting/improving a translation is viewed as a good thing rather than an attempt to subvert the cultural identity of the person who posted the original.

I'm happy to close a question in a "non-mathematical language" (say, outside of English, French, German, Russian, Japanese) single handedly, but for anything where I think that sufficiently many readers can comprehend what's going on that if it were inappropriate for some reason other than the langauge then the moderators would hear about it, I'd ignore if I didn't understand, and otherwise be perfectly content.

There's just too much risk of annoying people, in exchange for the dubious benefit of preventing a seemingly very unlikely, and as yet non-existent problem.

It seems like everybody agrees that generating a translation (even a crude one) is a good idea, or at least not harmful. I feel like this is pretty important to keep things well-integrated and keep from wasting peoples' time. The idea of having the original in the revision history was an attempt to bind the original to the translation more tightly than if they were just completely different posts. You're absolutely right that just having the original, then a horizontal rule, then a translation is a far better solution.

If someone doesn't have 2000+ rep, then I think it still makes sense to encourage them to post a translation (if that's something they're motivated to do) as a CW answer, and it can later be merged by someone who can edit the original. Extending this a bit, maybe it makes sense to start all translations as separate CW posts and merge them once they've become pretty good. That way the original poster is not penalized much (remember that a post is automatically converted to wiki if it is edited many times or by many users).

And I also don't like the idea of hiding so much of the original answer. I still think it is best to have a separate translation answer, so that the translator can be rewarded for his efforts, but if you really don't like that then append the translation to the answer and leave the original in place.

In particular, I really dislike the idea of replacing people's questions with an English translation as a community norm. I can see encouraging people with edit privileges to add an English translation to the post, but why hide the original in edit history?

Actually I had translated a 14 page French paper by hand, two years or so ago. It was very painful. Later I started to translate FAC and dropped it halfway out of frustration, though it was such a great paper.

The frustration in math overflow is infinitely less compared to those instances. I can understand essentially everything with a single click. A few idiosyncrasies are there of course, but nothing that hinders understanding. Let mother-tongue lovers stick to their language. We do not want people to drop their cultural identity. We are not here to build a mathematical tower of babel. That is the job of the software of google or altavista.

(1) Two actually separate posts would float around the answers list independently, which I think would make it harder to compare the original to the translation. If they're bound together as two versions in the revision history, it's obvious to everyone that you compare them by opening the revision history in a tab and tab back and forth (of course you can do this with two posts, but I think people would try to page-up page-down between them). This also ensures that there is a single comment thread for the answer. I admit it will tend to be long since it will include both comments about the translation and about the mathematics, but sometimes a comment you think is about the translation is actually a mistake in the math, or vice versa, so I view a single comment thread as a plus. One downside is that it would be harder to make edits to the original language version.

(2) I feel like the separate voting buckets is actually a downside. It makes posting in another language some sort of a special occasion, and it would be confusing to decide how to vote. Does the translator (whoever used Google first) really deserve as much rep as the poster? If not, when should you vote for the translation? What if the same person posted the answer and its translation? I really want translation to be automatic; just feed the original through Google and perhaps make some obvious corrections. In particular, I think it would be best if the person posting the answer also posted the translation immediately. If something is wrong with Google's translation, the original poster can probably fix it easily (he can probably read English fairly well if he's using MO). Even if he doesn't, everybody would understand that if something is amiss in the English version, the original is the first place they should look.

(1) The original is more visible, so it is more likely people will point out errors in the translation.

(2) The translator and the original poster can both get reputation for their work.

The main problem in my mind with non-English posts is that they invite fragmentation. The nightmare scenario is that MO hosts two or more essentially non-interacting communities, which would irritate everybody. A few posts in other languages isn't going to do it, but it certainly creates tension. My intuition is that we should exert a definite pressure for people to post in English.

Some notes about these particular answers:

• They're in French, which is a standard language for the topic. I think this makes them a little bit less of a problem.
• They're good. If the choices are to have them in French or not have them at all, then we want to have them in French. In this case I'm a bit skeptical that this is really the situation. Laurent posted a comment on one of his answers which was in perfect English. I understand that composing a comment in another language is easier than composing an answer, but the comment seems so well-composed that it's hard to imagine it would have been much more effort to post the answer in English. Moreover, he was clearly able to read the questions and the FAQ, ending the answer with "P.S.: I read the rules for this forum: it is nowhere written the questions and answers should be written in english !!!!!!!!" I'm not sure how to read that, but it's not hard to read it as ending with "So there!" I want to allow for the possibility that someone has something to offer and can't write it in English, but I would get annoyed with somebody using technical terms that most people interested in the post would have to spend five minutes looking up or figuring out just because it would take slightly more effort to add a sentence explaining what those terms mean. And if I were one of the people who put in the time to make sense of the terms, I'd edit the post to make it easier for others.
• They're answers, not questions. I think answers in another language are much less dangerous (from the point of view of community fragmentation) than questions in another language. If I want to know the answer to a question, and I see the answer posted in another language, then I'll do my best to make sense of it. On the other hand, if I see a question (suppose it's even in my field) in another language, I feel like it's much easier to just ignore it. I really want to avoid that. I'd much rather see questions in broken English with people could figuring out ambiguities in the comments and 2000+ rep users editing for clarity.

Proposed protocol (Edit: ignore this; see further comments)

What do people think about the following protocol for non-English posts?

If somebody really wants to post a question or answer in another language, they do it. Five minutes later, they (or somebody else) edits the post to replace it by an English translation, however crude (I think the results of just pushing the source through Google Translate are actually very good), and adds a line at the top saying "Original Arabic available in the edit history."

The bit about it being five minutes later is important because the system globs together edits occurring within five minutes of each other in the revision history, so if the original poster edits the post within five minutes of posting it, the original won't appear in the revision history.

This takes almost no additional effort on the part of the person posting, even if they know no English, it immediately and drastically reduces the risks and tensions of using many different languages, and the full text in its original language is available (completely rendered: here's an example) in a single click. I would also encourage 2000+ rep users to improve the translation (even better, give the improved translation to Google).

If it were possible to tag individual answers, I would recommend tagging non-English answers with the name of the language they're in. This would make it easy for somebody who wanted to spend some time translating foreign-language answers into English (which is the dominant language of the site) to find them. (I would try my hand at translating Fargues' answers myself, except that this isn't my area, and so I'm afraid I'd introduce errors.)

I suspect that if this site becomes popular enough among speakers of language X that people want to post in it, there will also be speakers of language X who have moderation ability, so moderation might not be an issue. In any case, let's worry about that if it happens.

Suppose I happily live in a middle-class nearly completely English-speaking suburban utopia and somebody moves in (pick up your choice your choice of French-speaking, Korean-speaking or something else). I would prefer if the new person spoke in English (I love to chat and so), but I can express this in a different way:

(1) You should speak English, or I'll come and beat you up

or

(2) You should speak English, or you'll have a hard time communicating with others

I hopefully don't need to explain why (2) is a better thing to suggest in real life.

In the case of MO, I'm sure any non-English-posting person will soon notice that posting in English allows more people to read his post and brings more reputation. So, I' m willing to bet that the "problem" will correct itself (edit: one of possible corrections is that it will be obvious to everyone that the particular non-English posts are so worthwhile that we will be happy about them).

Moreover, mathematicians (as a culture) are really polite and try not to duplicate posts, but in this case I could imagine another person posting an answer that translates Laurent F.'s answer, citing him, and grabbing some attention and reputation that Laurent could get. Once this happens, the motivation to write in English will again increase.