This post is very loosely related to this one regarding issues international users may have, but I'm covering different ground with this one.
The prevalent language used on the Stack Exchange network is English. I'd like to see a drop down field (or something like it), where one can select the native language for oneself within the profile.
I don't want to argue about implementation details like
Tool X, but the languages should be predefined if at all possible. The reasoning for that follows in the next section:
How I'd like to see this used
In my case the language chosen would be German, and if I post a question or an answer here on meta, I'd expect to see something similar to this:
Probably with a tooltip indicating the language in a textual way. This is why I think a predefined list of languages, or maybe even a list of flags, is a good idea, because that makes it easier to automatically have an image displayed that's related to the selected language.
This is not necessarily something that needs to go into flair, it really is only useful for asking/answering questions and posting comments. But it still could be a publicly visible field within the profile.
Why I think this is a good idea
Lots of reasons, the ones I came up with today (while driving for two hours on the motorway), are listed below in no particular order:
On edits of my posts like this one, I usually post something like a "thanks for editing, I'm not a native speaker" comment. With the proposed change, this would be totally obvious and not necessary anymore.
It would take a bit of the edge out of discussions like in the comments on this post. Some of it has to do with the fact that it wasn't obvious that the OP was not a native speaker. I agree there are other issues there, but that's beside the point for my intention here.
I'd think this would be almost invaluable on sites concerning other languages, like German, French, Italian, Japanese, plus whichever other ones are currently proposed at Area51 (I haven't checked, but I know I saw these four).
On the cooking site, there's some questions regarding Pizza and Pasta for example, and I have seen quite a few posts saying "I'm Italian, so ...". I haven't checked, but I'd expect to see the same sort of stuff regarding Chinese users and Chinese food, Japanese users and sushi questions etc. Again, this change would make that unnecessary for most cases.
It would help mitigating the issues mentioned in this answer.
Feel free to comment if you have more ideas.
Why this may be a bad idea
I can only think of one reason here: Someone sees that the OP is French, German or whatever language, and posts a comment or answer in that language. This would be a no-go, the only exception being a site for that particular language, as I think there's a policy allowing it.
Still, this won't break my proposal. One could instead of a flag just show some kind of indicator that the poster is not a native speaker.
It is not my intent to question the non-English question policy with this proposal.
This is not meant to be a replacement, nor is it necessarily identical, to the user location that can already be entered in the profile.
It's easily understandable that someone that grew up in Italy can for example live in Germany, but he'd (most likely) select Italian as native language.
This is not necessarily an indication of all languages a user may be fluent in. For example, someone living in Canada, may well be fluent in French and in English, so would probably pick English. Likewise, someone in Switzerland may be fluent in French and/or German and/or Italian, here it wouldn't matter much which one he preferred. It is meant to be as an indicator to a native English speaker that the poster may not be as fluent in English as they appear to be.