Index: wysiwyg.admin.inc
===================================================================
--- wysiwyg.admin.inc	(revision 2)
+++ wysiwyg.admin.inc	(working copy)
@@ -95,7 +95,7 @@ function wysiwyg_profile_form($form_stat
     '#type' => 'select',
     '#title' => t('Language'),
     '#default_value' => $profile->settings['language'],
-    '#options' => drupal_map_assoc(array('ar', 'ca', 'cs', 'cy', 'da', 'de', 'el', 'en', 'es', 'fa', 'fi', 'fr', 'fr_ca', 'he', 'hu', 'is', 'it', 'ja', 'ko', 'nb', 'nl', 'nn', 'pl', 'pt', 'pt_br', 'ru', 'ru_KOI8-R', 'ru_UTF-8', 'si', 'sk', 'sv', 'th', 'zh_cn', 'zh_tw', 'zh_tw_utf8')),
+    '#options' => drupal_map_assoc(array('USER_DEFAULT', 'ar', 'ca', 'cs', 'cy', 'da', 'de', 'el', 'en', 'es', 'fa', 'fi', 'fr', 'fr_ca', 'he', 'hu', 'is', 'it', 'ja', 'ko', 'nb', 'nl', 'nn', 'pl', 'pt', 'pt_br', 'ru', 'ru_KOI8-R', 'ru_UTF-8', 'si', 'sk', 'sv', 'th', 'zh_cn', 'zh_tw', 'zh_tw_utf8')),
     '#description' => t('The language to use for the editor interface. Language codes are based on the <a href="http://www.loc.gov/standards/iso639-2/englangn.html">ISO-639-2</a> format.'),
   );
 
Index: wysiwyg.module
===================================================================
--- wysiwyg.module	(revision 2)
+++ wysiwyg.module	(working copy)
@@ -162,6 +162,12 @@ function wysiwyg_process_form(&$form) {
               // Check editor theme (and reset it if not/no longer available).
               $theme = wysiwyg_get_editor_themes($profile, (isset($profile->settings['theme']) ? $profile->settings['theme'] : ''));
 
+              // Language settings.
+              if ($profile->settings['language'] == 'USER_DEFAULT') {
+                global $language;
+                $profile->settings['language'] = $language->language;
+              }
+
               // Add plugin settings (first) for this input format.
               wysiwyg_add_plugin_settings($profile);
               // Add profile settings for this input format.