We currently localise the platform for unauthenticated users based on their browser language settings, with no option to change the language within the platform. We do however support explicit language change for authenticated users, but only after navigating to the user profile.
Ideally, we should allow users (both logged in and not) to change the interface language from wherever they are.
Ideally - this would take the form of a dropdown option in the site navigation bar. If the user is not logged in, then this can just take effect for the duration of the user's session. If they are logged in, it should update their user profile language preference.