BuddyPress.org

thanks DJPaul.

FYI: After reading http://www.studiograsshopper.ch/web-development/multilingual-wordpress-setting-up-wordpress/ I realized that the basic setting in wp-config could be changed (from define (‘WPLANG’, ”); to define (‘WPLANG’, ‘es_ES’); which -I think- adds Spanish (and not replaces the main language?) support.

Not sure if this setting does anything as the admin of the main blog could already choose es_ES in his blog settings (so ALL users see the blog in Spanish instead of all in English) before I ‘added’ Spanish in wp-config. (As long as the language file was uploaded to /languages of course).

Anyway, it does not change anything

– The home/community page/main blog and the buddy bar are still in the language the admin has chosen for it, not the language of the logged-in user (or a logged-out/new user for that matter).