BuddyPress.org

I just did this last night, using the .pot/.po/.mo thing, and I HIGHLY recommend grabbing poedit from Sourceforge rather than editing the text file manually. It pulls together all instances of a term and lets you edit once, rather than having to find them all.

It’ll give you a couple of critical errors after you hit save to generate the .mo file — just go to the Catalog — Setiings dialog, change the Team to your website name and clear out the plural forms thing at the bottom, and all seems to work well.

Then just add the bp-custom function to call the new language file and you’re good to go. Very easy, and I’ve changed a whole bunch of verbiage across my site, no problems.