Index: user.module
===================================================================
RCS file: /cvs/drupal/drupal/modules/user/user.module,v
retrieving revision 1.892.2.11
diff -u -r1.892.2.11 user.module
--- user.module	14 Jan 2009 23:34:08 -0000	1.892.2.11
+++ user.module	22 Jan 2009 10:28:16 -0000
@@ -2276,6 +2276,7 @@
  */
 function user_register_submit($form, &$form_state) {
   global $base_url;
+  global $language;
   $admin = user_access('administer users');
 
   $mail = $form_state['values']['mail'];
@@ -2305,7 +2306,7 @@
   // user data.
   unset($form_state['values']['form_token'], $form_state['values']['submit'], $form_state['values']['op'], $form_state['values']['notify'], $form_state['values']['form_id'], $form_state['values']['affiliates'], $form_state['values']['destination']);
 
-  $merge_data = array('pass' => $pass, 'init' => $mail, 'roles' => $roles);
+  $merge_data = array('pass' => $pass, 'init' => $mail, 'roles' => $roles, 'language' => $language->language);
   if (!$admin) {
     // Set the user's status because it was not displayed in the form.
     $merge_data['status'] = variable_get('user_register', 1) == 1;