Re: Preferred langauge in user's profile settings
There is a multilingual plugin for BP available which does this:
I don’t know if it’s compatible with the BP 1.1 or the upcoming 1.2. I need this as well so we should look into it then
Also take a look at this ticket I made today: https://trac.buddypress.org/ticket/1593
If the “supergroup” feature would be implemented it would mean that you could make different “homes” for different countries/regions and still have a central homepage where all sitewide content is shown.