That discussion has been going for a while 😃 but I don't really see where this is going.
My thoughts, addressed to nobody in particular:
If you're looking for something you can do right now without any development or cost, you can use tags to create localized sections of your forum. Nothing fancy, but this might suit you.
For anything else, you will likely need to develop or hire somebody to create an extension for you. Everything that has been mentioned here so far seems perfectly feasible in Flarum today.
For example I believe the following options can be realistically implemented without too much difficulties:
- Store the language the post has been created with
- Hide or auto-translate posts that aren't in the current language
- Allow a user to specify which languages he understands
- Add conditional BBCode to show some text depending on the value of the language switcher
- Add a translation feature to write a translated version of full posts
- If you allow anybody to translate, add new screens for translators, and probably moderation tools to go with it
- Have unified discussion but separate comment threads for each languages
A lot depends on what you want to translate (whole discussions, first post, individual posts, specific content in a post, profile pages, content from another extension), whether you will be isolating the various languages and who will be translating (you, a computer, the author, other members).
And then we can talk about the required database changes 😉