diff -u b/core/lib/Drupal/Core/Language/Language.php b/core/lib/Drupal/Core/Language/Language.php
--- b/core/lib/Drupal/Core/Language/Language.php
+++ b/core/lib/Drupal/Core/Language/Language.php
@@ -21,13 +21,13 @@
    *
    * @var array
    */
-  public static $defaultValues = [
+  public static $defaultValues = array(
     'id' => 'en',
     'name' => 'English',
     'direction' => self::DIRECTION_LTR,
     'weight' => 0,
     'locked' => FALSE,
-  ];
+  );
 
   // Properties within the Language are set up as the default language.
 
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
@@ -335,23 +335,23 @@
   /**
    * The 6 official languages used at the United Nations.
    *
-   * This list is based on
-   * http://www.un.org/en/aboutun/languages.shtml/ and it
+   * This list is based 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 is an array of English and native names.
+   *   An array with language codes as keys, and English and native language
+   *   names as values. Language name information is an array of English and
+   *   native names.
    */
   public static function getUnitedNationsLanguageList() {
-    return array(
-      'ar' => array('Arabic', /* Left-to-right marker "‭" */ 'العربية', LanguageInterface::DIRECTION_RTL),
-      'zh-hans' => array('Chinese, Simplified', '简体中文'),
-      'en' => array('English', 'English'),
-      'fr' => array('French', 'Français'),
-      'ru' => array('Russian', 'Русский'),
-      'es' => array('Spanish', 'Español'),
-    );
+    return [
+      'ar' => ['Arabic', /* Left-to-right marker "‭" */ 'العربية', LanguageInterface::DIRECTION_RTL],
+      'zh-hans' => ['Chinese, Simplified', '简体中文'],
+      'en' => ['English', 'English'],
+      'fr' => ['French', 'Français'],
+      'ru' => ['Russian', 'Русский'],
+      'es' => ['Spanish', 'Español'],
+    ];
   }
 
   /**
diff -u b/core/modules/ckeditor/config/schema/ckeditor.schema.yml b/core/modules/ckeditor/config/schema/ckeditor.schema.yml
--- b/core/modules/ckeditor/config/schema/ckeditor.schema.yml
+++ b/core/modules/ckeditor/config/schema/ckeditor.schema.yml
@@ -38,9 +38,9 @@
   type: mapping
   label: 'Language'
   mapping:
-    language_list_type:
+    language_list:
       type: string
-      label: 'Language list type ID'
+      label: 'Language list ID'
 
 # Plugin \Drupal\ckeditor\Plugin\ckeditor\plugin\StylesCombo
 ckeditor.plugin.stylescombo:
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
@@ -44,9 +44,7 @@
    * {@inheritdoc}
    */
   public function getLibraries(Editor $editor) {
-    return array(
-      'ckeditor/drupal.ckeditor.plugins.language',
-    );
+    return ['ckeditor/drupal.ckeditor.plugins.language'];
   }
 
   /**
@@ -54,13 +52,13 @@
    */
   public function getConfig(Editor $editor) {
     $language_list = [];
-    $config = ['language_list_type' => 'un'];
+    $config = ['language_list' => 'un'];
     $settings = $editor->getSettings();
     if (isset($settings['plugins']['language'])) {
       $config = $settings['plugins']['language'];
     }
 
-    $predefined_languages = ($config['language_list_type'] === 'all') ?
+    $predefined_languages = ($config['language_list'] === 'all') ?
       LanguageManager::getStandardLanguageList() :
       LanguageManager::getUnitedNationsLanguageList();
 
@@ -88,15 +86,15 @@
    * {@inheritdoc}
    */
   public function getButtons() {
-    return array(
-      'Language' => array(
+    return [
+      'Language' => [
         'label' => $this->t('Language'),
         'image_alternative' => [
           '#type' => 'inline_template',
           '#template' => '<a href="#" class="cke-icon-only" role="button" title="' . $this->t('Language') . '" aria-label="' . $this->t('Language') . '"><span class="cke_button_icon cke_button__language_icon">' . $this->t('Language') . '</span></a>',
         ],
-      ),
-    );
+      ],
+    ];
   }
 
   /**
@@ -104,22 +102,22 @@
    */
   public function settingsForm(array $form, FormStateInterface $form_state, Editor $editor) {
     // Defaults.
-    $config = ['language_list_type' => 'un'];
+    $config = ['language_list' => 'un'];
     $settings = $editor->getSettings();
     if (isset($settings['plugins']['language'])) {
       $config = $settings['plugins']['language'];
     }
 
     $predefined_languages = LanguageManager::getStandardLanguageList();
-    $form['language_list_type'] = array(
-      '#title' => $this->t('Language list type'),
+    $form['language_list'] = array(
+      '#title' => $this->t('Language list'),
       '#title_display' => 'invisible',
       '#type' => 'select',
       '#options' => [
         'un' => $this->t("United Nations' official languages"),
         'all' => $this->t('All @count languages', ['@count' => count($predefined_languages)]),
       ],
-      '#default_value' => $config['language_list_type'],
+      '#default_value' => $config['language_list'],
       '#description' => $this->t('The list of languages to show in the language dropdown. The basic list will only show the <a href=":url">six official languages of the UN</a>. The extended list will show all @count languages that are available in Drupal.', [
         ':url' => Url::fromUri('http://www.un.org/en/aboutun/languages.shtml/')->toString(),
         '@count' => count($predefined_languages),
diff -u b/core/modules/ckeditor/src/Plugin/Editor/CKEditor.php b/core/modules/ckeditor/src/Plugin/Editor/CKEditor.php
--- b/core/modules/ckeditor/src/Plugin/Editor/CKEditor.php
+++ b/core/modules/ckeditor/src/Plugin/Editor/CKEditor.php
@@ -135,7 +135,7 @@
           ),
         ),
       ),
-      'plugins' => ['language' => ['language_list_type' => 'un']],
+      'plugins' => ['language' => ['language_list' => 'un']],
     );
   }
 
diff -u b/core/modules/ckeditor/src/Tests/CKEditorAdminTest.php b/core/modules/ckeditor/src/Tests/CKEditorAdminTest.php
--- b/core/modules/ckeditor/src/Tests/CKEditorAdminTest.php
+++ b/core/modules/ckeditor/src/Tests/CKEditorAdminTest.php
@@ -109,7 +109,7 @@
           ),
         ),
       ),
-      'plugins' => ['language' => ['language_list_type' => 'un']],
+      'plugins' => ['language' => ['language_list' => 'un']],
     );
     $this->assertIdentical($this->castSafeStrings($ckeditor->getDefaultSettings()), $expected_default_settings);
 
@@ -148,7 +148,7 @@
     $expected_settings['plugins']['stylescombo']['styles'] = '';
     $editor = entity_load('editor', 'filtered_html');
     $this->assertTrue($editor instanceof Editor, 'An Editor config entity exists now.');
-    $this->assertEqual($expected_settings, $editor->getSettings(), 'The Editor config entity has the correct settings.');
+    $this->assertIdentical($expected_settings, $editor->getSettings(), 'The Editor config entity has the correct settings.');
 
     // Configure the Styles plugin, and ensure the updated settings are saved.
     $this->drupalGet('admin/config/content/formats/manage/filtered_html');
@@ -159,7 +159,7 @@
     $expected_settings['plugins']['stylescombo']['styles'] = "h1.title|Title\np.callout|Callout\n\n";
     $editor = entity_load('editor', 'filtered_html');
     $this->assertTrue($editor instanceof Editor, 'An Editor config entity exists.');
-    $this->assertEqual($expected_settings, $editor->getSettings(), 'The Editor config entity has the correct settings.');
+    $this->assertIdentical($expected_settings, $editor->getSettings(), 'The Editor config entity has the correct settings.');
 
     // Change the buttons that appear on the toolbar (in JavaScript, this is
     // done via drag and drop, but here we can only emulate the end result of
@@ -175,7 +175,7 @@
     $this->drupalPostForm(NULL, $edit, t('Save configuration'));
     $editor = entity_load('editor', 'filtered_html');
     $this->assertTrue($editor instanceof Editor, 'An Editor config entity exists.');
-    $this->assertEqual($expected_settings, $editor->getSettings(), 'The Editor config entity has the correct settings.');
+    $this->assertIdentical($expected_settings, $editor->getSettings(), 'The Editor config entity has the correct settings.');
 
     // Check that the markup we're setting for the toolbar buttons (actually in
     // JavaScript's drupalSettings, and Unicode-escaped) is correctly rendered.
@@ -203,7 +203,7 @@
     $this->assertTrue(count($ultra_llama_mode_checkbox) === 1, 'The "Ultra llama mode" checkbox exists and is not checked.');
     $editor = entity_load('editor', 'filtered_html');
     $this->assertTrue($editor instanceof Editor, 'An Editor config entity exists.');
-    $this->assertEqual($expected_settings, $editor->getSettings(), 'The Editor config entity has the correct settings.');
+    $this->assertIdentical($expected_settings, $editor->getSettings(), 'The Editor config entity has the correct settings.');
 
     // Finally, check the "Ultra llama mode" checkbox.
     $this->drupalGet('admin/config/content/formats/manage/filtered_html');
@@ -217,7 +217,7 @@
     $expected_settings['plugins']['llama_contextual_and_button']['ultra_llama_mode'] = TRUE;
     $editor = entity_load('editor', 'filtered_html');
     $this->assertTrue($editor instanceof Editor, 'An Editor config entity exists.');
-    $this->assertEqual($expected_settings, $editor->getSettings());
+    $this->assertIdentical($expected_settings, $editor->getSettings());
   }
 
   /**
@@ -282,7 +282,7 @@
     $expected_settings['plugins']['stylescombo']['styles'] = '';
     $editor = entity_load('editor', 'amazing_format');
     $this->assertTrue($editor instanceof Editor, 'An Editor config entity exists now.');
-    $this->assertEqual($this->castSafeStrings($expected_settings), $this->castSafeStrings($editor->getSettings()), 'The Editor config entity has the correct settings.');
+    $this->assertIdentical($this->castSafeStrings($expected_settings), $this->castSafeStrings($editor->getSettings()), 'The Editor config entity has the correct settings.');
   }
 
 }
diff -u b/core/modules/ckeditor/tests/src/Unit/Plugin/CKEditorPlugin/LanguageTest.php b/core/modules/ckeditor/tests/src/Unit/Plugin/CKEditorPlugin/LanguageTest.php
--- b/core/modules/ckeditor/tests/src/Unit/Plugin/CKEditorPlugin/LanguageTest.php
+++ b/core/modules/ckeditor/tests/src/Unit/Plugin/CKEditorPlugin/LanguageTest.php
@@ -41,13 +41,13 @@
    *
    * @dataProvider providerGetConfig
    */
-  public function testGetConfig($language_list_type, $expected_number) {
+  public function testGetConfig($language_list, $expected_number) {
     $editor = $this->getMockBuilder('Drupal\editor\Entity\Editor')
       ->disableOriginalConstructor()
       ->getMock();
     $editor->expects($this->once())
       ->method('getSettings')
-      ->willReturn(['plugins' => ['language' => ['language_list_type' => $language_list_type]]]);
+      ->willReturn(['plugins' => ['language' => ['language_list' => $language_list]]]);
 
     $config = $this->plugin->getConfig($editor);
 
diff -u b/core/themes/stable/css/ckeditor/plugins/language/ckeditor.language.css b/core/themes/stable/css/ckeditor/plugins/language/ckeditor.language.css
--- b/core/themes/stable/css/ckeditor/plugins/language/ckeditor.language.css
+++ b/core/themes/stable/css/ckeditor/plugins/language/ckeditor.language.css
@@ -8,21 +8,12 @@
- * border. We also append the value of the tag between brackets, eg: '(en)'.
+ * border. We also append the value of the tag between brackets, for example:
+ * '(en)'. Since the html element has a 'lang' attribute too we only target
+ * elements within the html scope.
  */
-[lang] {
+html [lang] {
   outline: 1px dotted gray;
 }
-[lang]:after {
+html [lang]:after {
   content: " ("attr(lang)")";
   font-size: 10px;
   color: #666;
 }
-
-/**
- * The HTML element has a default 'lang' attribute.
- * We don't want styling there.
- */
-html[lang] {
-  outline: none;
-}
-html[lang]:after {
-  content: none;
-}