diff -uprN a/ckeditor.module b/ckeditor.module
--- a/ckeditor.module	2013-01-09 10:11:51.000000000 -0200
+++ b/ckeditor.module	2013-01-11 12:30:02.000000000 -0200
@@ -753,6 +753,9 @@ function ckeditor_process_textarea($elem
     if ($conf['auto_lang']=="f") {
       $settings[$textarea_id]['language'] = $conf['lang'];
     }
+    else if ($conf['auto_lang']=="d") {
+      $settings[$textarea_id]['language'] = $language->language;
+    }
     if (isset($element['#scayt_language'])) {
       $settings[$textarea_id]['scayt_sLang'] = $element['#scayt_language'];
     }
diff -uprN a/includes/ckeditor.admin.inc b/includes/ckeditor.admin.inc
--- a/includes/ckeditor.admin.inc	2013-01-09 10:11:51.000000000 -0200
+++ b/includes/ckeditor.admin.inc	2013-01-11 13:31:35.000000000 -0200
@@ -764,7 +764,8 @@ function ckeditor_admin_profile_form($fo
     '#title' => t('Auto-detect language'),
     '#default_value' => !empty($profile->settings['auto_lang']) ? $profile->settings['auto_lang'] : 't',
     '#options' => array(
-      't' => t('Enabled'),
+      't' => t('Enabled (browser language)'),
+      'd' => t('Enabled (Drupal language)'),
       'f' => t('Disabled')
     ),
     '#description' => t('Automatically detect the user language.')
diff -uprN a/includes/ckeditor.user.inc b/includes/ckeditor.user.inc
--- a/includes/ckeditor.user.inc	2013-01-09 10:11:51.000000000 -0200
+++ b/includes/ckeditor.user.inc	2013-01-11 12:30:02.000000000 -0200
@@ -123,7 +123,8 @@ function ckeditor_user_delegate($type, $
         '#title' => t('Auto-detect language'),
         '#default_value' => isset($user->ckeditor_auto_lang) ? $user->ckeditor_auto_lang : (isset($profile->settings['auto_lang']) ? $profile->settings['auto_lang'] : 't'),
         '#options' => array(
-          't' => t('Yes'),
+          't' => t('Yes (browser language)'),
+          'd' => t('Yes (Drupal language)'),
           'f' => t('No')
         ),
         '#description' => t('Automatically detect the user language.')