BuddyPress.org

Kenneth,

Make sure you are putting the MO language file in the right place — it goes in “{your-buddypress-install}/bp-languages”. Also make sure it’s named correctly with “buddypress-” and the WPLANG locale definition (like “fr_FR” for French).

Then make sure you have defined your language in “wp-config.php”.

You can see all the details at Translating WordPress.

That page explains:

Set WPLANG inside of wp-config.php to your chosen language. For example, if you wanted to use French, you would have:

define ('WPLANG', 'fr_FR');