I haven’t made it yet, but I’d like to. What’s been holding me back is that there’s a problem that if the locale is changed for an anonymous user on a forum that is using a CDN, the wrong locale may be served to the next anonymous user on their first request to the forum.
See:
It’s a solvable problem, possibly doing something like this: Swedish? meta just showed me the UI in Swedish - #10 by simon
For sites that aren’t using a CDN, this would be a fairly simple plugin. I think something like this could work as the UI:
Clicking on the ‘globe’ icon would open up a menu-panel that contains a locale switcher similar to the one in the admin section and a button that says something like ‘Reload Locale.’