Most user fields are available to be updated via Mass Update & available to filter on, but language isn't.
|What problem will this feature solve?:|
During an implementation large volumes of user records are uploaded, the user record fields are updated at the point of import but things can change and mistakes made. The only way to update fields is mass update or individually updating each record. As filters to the User Index are re-set after each record is updated, this is a lengthy task if the field is not available to filter on or to be able to mass update.