Step 1: Upload a MU language file to active the language select menu in “Site Admin” – “Options” page. This will make you can select sitewide default language.
Step 2: Upload a BP language file. And its language will been changed with MU at same time.
For example: I uploaded a file named “zh_CN.mo” for MU in “wp-content/languages/”. And now, In “Site Admin” – “Options” it will display a languages select menu. And in “Setting” – “General” will too. Now,I can change sitewide language or my own site language.
At this time, if I want to change BP’s language, I just need to upload a file “buddypress-zh_CN.mo” file in “wp-content/mu-plugins/bp-languages”.
You can test on my site, And I already translated BP and MU to chinese.
