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
@@ -353,15 +353,15 @@
   }
 
   /**
-   * The official languages used at the United Nations with
-   * their English and native names.
+   * The 6 official languages used at the United Nations.
    *
-   * This list is bases on http://www.un.org/en/aboutun/languages.shtml/ and
+   * This list is bases on
+   * http://www.un.org/en/aboutun/languages.shtml/ and it
    * uses the same format as getStandardLanguageList().
    *
    * @return array
    *   An array of language code to language name information.
-   *   Language name information itself is an array of English and native names.
+   *   Language name information is an array of English and native names.
    */
   public static function getUnitedNationsLanguageList() {
     return array(
reverted:
--- b/core/modules/ckeditor/config/schema/ckeditor.schema.yml
+++ a/core/modules/ckeditor/config/schema/ckeditor.schema.yml
@@ -41,4 +41,3 @@
     styles:
       type: string
       label: 'List of styles'
-
diff -u b/core/modules/ckeditor/src/Plugin/CKEditorPlugin/Language.php b/core/modules/ckeditor/src/Plugin/CKEditorPlugin/Language.php
--- b/core/modules/ckeditor/src/Plugin/CKEditorPlugin/Language.php
+++ b/core/modules/ckeditor/src/Plugin/CKEditorPlugin/Language.php
@@ -64,6 +64,9 @@
       LanguageManager::getStandardLanguageList() :
       LanguageManager::getUnitedNationsLanguageList();
 
+    // Generate the language_list setting as expected by the CKEditor Language
+    // plugin, but key the values by the full language name so that we can
+    // sort them later on.
     foreach ($predefined_languages as $langcode => $language) {
       $english_name = $language[0];
       $direction = empty($language[2]) ? NULL : $language[2];
@@ -89,8 +92,8 @@
   public function getButtons() {
     return array(
       'Language' => array(
-        'label' => t('Language'),
-        'image_alternative' => '<a href="#" class="cke-icon-only cke_ltr" role="button" title="' . t('Language') . '" aria-label="' . t('Language') . '"><span class="cke_button_icon cke_button__language_icon">' . t('Language') . '<span class="ckeditor-button-arrow"></span></span></a>',
+        'label' => $this->t('Language'),
+        'image_alternative' => '<a href="#" class="cke-icon-only cke_ltr" role="button" title="' . $this->t('Language') . '" aria-label="' . $this->t('Language') . '"><span class="cke_button_icon cke_button__language_icon">' . $this->t('Language') . '<span class="ckeditor-button-arrow"></span></span></a>',
       ),
     );
   }
@@ -99,6 +102,7 @@
    * {@inheritdoc}
    */
   public function settingsForm(array $form, FormStateInterface $form_state, Editor $editor) {
+    // Defaults.
     $config = array('list_type' => 'un');
     $settings = $editor->getSettings();
     if (isset($settings['plugins']['language'])) {
@@ -107,12 +111,12 @@
 
     $predefined_languages = LanguageManager::getStandardLanguageList();
     $form['list_type'] = array(
-      '#title' => t('Language list type'),
+      '#title' => $this->t('Language list type'),
       '#title_display' => 'invisible',
       '#type' => 'select',
       '#options' => array(
-        'un' => t('United Nations subset'),
-        'all' => t('All @count languages', array('@count' => sizeof($predefined_languages))),
+        'un' => $this->t('United Nations subset'),
+        'all' => $this->t('All @count languages', array('@count' => sizeof($predefined_languages))),
       ),
       '#default_value' => $config['list_type'],
       '#description' => $this->t('The list of languages to show in the language dropdown. The basic list will only show the <a href="@url">six official languages of the UN</a>. The extended list will show all @count languages that are available in Drupal.', array(