Question Multilingual site

I’m not sure I understand the way Kunena works well enough to even ask the right questions, but I’ll try.

What’s the best way to set it up so that users can choose a default language and can swap languages as they can do with regular content? Do I duplicate Kunena Menu and translate that?

I realise that it also needs the translated component, but it’s a general overview of how it fits together that I’m looking for.

Thanks in advance.

Yes it's possible and you're right, you need copies of the Kunena menu items for all extra languages. Association between all menu items are not absolutely necessary, I don't think, the users want to switch the language within the forum everywhere (example at the tab profile).

But there are a downer. If you want the forums completely separate, you can use only once a top level (container for categories) for each languages (see image).
And here a example on my testpage: Forum multilingual