Index: preserve_language.module
===================================================================
RCS file: /cvs/drupal-contrib/contributions/modules/preserve_language/preserve_language.module,v
retrieving revision 1.5
diff -u -r1.5 preserve_language.module
--- preserve_language.module	10 Nov 2008 11:27:19 -0000	1.5
+++ preserve_language.module	13 Nov 2008 14:02:03 -0000
@@ -19,6 +19,25 @@
 }
 
 /**
+ * Implementation of form_alter() for "locale_languages_overview_form" form
+ */
+function preserve_language_form_locale_languages_overview_form_alter(&$form, &$form_state) {
+  if (!empty($form_state['post']))
+    return;
+    
+  $language = language_default();
+  $langs = language_list('prefix');
+  
+  if (isset($langs[''])) {
+    $empty_prefix = $langs[''];
+    if ($empty_prefix->prefix == '' && $empty_prefix->language != $language->language) {
+        drupal_set_message(t('Seems that an empty path-prefix is setted to a non-default language. The empty path-prefix language is setted for !lang language.',
+          array('!lang' => l(t($empty_prefix->native), 'admin/settings/language/edit/'. $empty_prefix->language))), 'warning');
+      }
+  }
+}
+
+/**
  * Implementation of hook_form_alter()
  */
 function preserve_language_form_alter(&$form, $form_state, $form_id) {