Hi Roy,
This translation is contained in the BuddyPress plugin. It contain a POT file that can be translated under the languages directory. You should find this file in wp-content/plugins/buddypress/buddypress.pot
Usually, we recommend to rename both translated files buddypress-your-language-code.mo
and buddypress-your-language-code.po
. Then, please replace from the file name by the language code of your choice, for instance fr_FR for french.
Finally, the best practice is to move the files in the plugins languages directory of your whole website: wp-content/languages/plugins
directory. There, you will find the translation for other plugins.
This will also ensure that the files will not be lost during any future update.
Best regards,