Hi there,
Actually, those language you attached is controlled by the module's title itself as listed below at
Backend>Extension>Module
Leaderboard = mod_easysocial_leaderboard
Recent Albums = mod_easysocial_albums
Recent Users = mod_easysocial_users
Search For people = mod_easysocial_dating_search
Online Users = mod_easysocial_users
And you can find this language string at COM_EASYSOCIAL_PEOPLE at this path
language/*your-current-language/*your-current-language.com_easysocial.ini
Please give it a try and see how it goes