Index: modules/user/user.module
===================================================================
RCS file: /cvs/drupal/drupal/modules/user/user.module,v
retrieving revision 1.1195
diff -u -p -r1.1195 user.module
--- modules/user/user.module	23 Aug 2010 14:53:50 -0000	1.1195
+++ modules/user/user.module	25 Aug 2010 12:26:58 -0000
@@ -3334,7 +3334,7 @@ function _user_mail_notify($op, $account
   $notify = variable_get('user_mail_' . $op . '_notify', $default_notify);
   if ($notify) {
     $params['account'] = $account;
-    $language = $language ? $language : user_preferred_language($account);
+    $language = $language ? $language : language_default();
     $mail = drupal_mail('user', $op, $account->mail, $language, $params);
     if ($op == 'register_pending_approval') {
       // If a user registered requiring admin approval, notify the admin, too.