Some time ago, we talked about translating some Drupal site variables such as site name through defining them in the sites/default/settings.php.
Drupal – Site Name Translation
 

If you want to translate those registration related text which are configured @ Administer -> User management -> User settings, add those variables in sites/default/settings.php.

$conf['i18n_variables'] = array(
  // Site name, slogan, mission, etc..
  'site_name',
  'site_slogan',
  'site_mission',
  'site_footer',
  // User email variables
  'user_mail_password_reset_body',
  'user_mail_password_reset_subject',
  'user_mail_register_admin_created_body',
  'user_mail_register_admin_created_subject',
  'user_mail_register_no_approval_required_body',
  'user_mail_register_no_approval_required_subject',
  'user_mail_register_pending_approval_body',
  'user_mail_register_pending_approval_subject',
  'user_mail_status_activated_body',
  'user_mail_status_activated_subject',
  'user_mail_status_blocked_body',
  'user_mail_status_blocked_subject',
  'user_mail_status_deleted_body',
  'user_mail_status_deleted_subject',
  'user_picture_guidelines',
  'user_registration_help',
);

Those variables are turned to multilingual.

 

Done =)

Reference: How to translate “User registration guidelines” in /admin/user/settings?