commit 29381fccb4ce0a52d62c5053641d6d365ecb4611
Author: Erik Stielstra <info@erikstielstra.nl>
Date:   Sun Oct 5 13:31:43 2014 +0200

    #96

diff --git a/core/lib/Drupal/Core/Language/LanguageManager.php b/core/lib/Drupal/Core/Language/LanguageManager.php
index 99f58cf..f69bb5d 100644
--- a/core/lib/Drupal/Core/Language/LanguageManager.php
+++ b/core/lib/Drupal/Core/Language/LanguageManager.php
@@ -391,7 +391,7 @@ protected function languageFilter(array $languages, $flags = LanguageInterface::
       // if we're acting on a global object, so clone the object first.
       $default = clone $default;
       $default->name = $this->t("Site's default language (@lang_name)", array('@lang_name' => $default->name));
-      $filtered_languages['site_default'] = $default;
+      $filtered_languages[LanguageInterface::STATE_SITE_DEFAULT] = $default;
     }
 
     foreach ($languages as $id => $language) {