diff -u b/core/lib/Drupal/Core/Language/LanguageManager.php b/core/lib/Drupal/Core/Language/LanguageManager.php
--- b/core/lib/Drupal/Core/Language/LanguageManager.php
+++ b/core/lib/Drupal/Core/Language/LanguageManager.php
@@ -88,13 +88,13 @@
     // access names and descriptions of the default language types.
     return array(
       LanguageInterface::TYPE_INTERFACE => array(
-        'name' => t('User interface text'),
-        'description' => t('Order of language detection methods for user interface text. If a translation of user interface text is available in the detected language, it will be displayed.'),
+        'name' => $this->t('User interface text'),
+        'description' => $this->t('Order of language detection methods for user interface text. If a translation of user interface text is available in the detected language, it will be displayed.'),
         'locked' => TRUE,
       ),
       LanguageInterface::TYPE_CONTENT => array(
-        'name' => t('Content'),
-        'description' => t('Order of language detection methods for content. If a version of content is available in the detected language, it will be displayed.'),
+        'name' => $this->t('Content'),
+        'description' => $this->t('Order of language detection methods for content. If a version of content is available in the detected language, it will be displayed.'),
         'locked' => TRUE,
       ),
       LanguageInterface::TYPE_URL => array(