diff --git a/core/modules/ckeditor/src/CKEditorPluginButtonsInterface.php b/core/modules/ckeditor/src/CKEditorPluginButtonsInterface.php
index 11d142a..55912bb 100644
--- a/core/modules/ckeditor/src/CKEditorPluginButtonsInterface.php
+++ b/core/modules/ckeditor/src/CKEditorPluginButtonsInterface.php
@@ -48,6 +48,10 @@
    *   - internal_button: Identifier of internal button.
    *   - image_internal_has_rtl: Flag indicating whether there's RTL version
    *     available.
+   *   - image_alternative: If this button does not render as an image, specify
+   *     an HTML string representing the contents of this button.
+   *   - image_alternative_rtl: Similar to image_alternative, but a
+   *     right-to-left version.
    *   - attributes: An array of HTML attributes which should be added to this
    *     button when rendering the button in the administrative section for
    *     assembling the toolbar.
diff --git a/core/modules/ckeditor/src/Plugin/CKEditorPlugin/Internal.php b/core/modules/ckeditor/src/Plugin/CKEditorPlugin/Internal.php
index e2d6e73..4e219ae 100644
--- a/core/modules/ckeditor/src/Plugin/CKEditorPlugin/Internal.php
+++ b/core/modules/ckeditor/src/Plugin/CKEditorPlugin/Internal.php
@@ -100,6 +100,7 @@ public function getConfig(Editor $editor) {
       'resize_dir' => 'vertical',
       'justifyClasses' => array('text-align-left', 'text-align-center', 'text-align-right', 'text-align-justify'),
       'entities' => FALSE,
+      'image_alternative' => '<a href="#" role="button" aria-label="' . t('Button separator') . '" class="ckeditor-separator"></a>',
     );
 
     // Add the allowedContent setting, which ensures CKEditor only allows tags
diff --git a/core/modules/ckeditor/src/Plugin/CKEditorPlugin/StylesCombo.php b/core/modules/ckeditor/src/Plugin/CKEditorPlugin/StylesCombo.php
index f2f9721..79dc2e4 100644
--- a/core/modules/ckeditor/src/Plugin/CKEditorPlugin/StylesCombo.php
+++ b/core/modules/ckeditor/src/Plugin/CKEditorPlugin/StylesCombo.php
@@ -62,6 +62,7 @@ public function getButtons() {
         'button_text' => t('Styles'),
         'internal_button' => 'styles',
         'is_dropdown' => TRUE,
+        'image_alternative' => '<a href="#" role="button" aria-label="' . t('Styles') . '"><span class="ckeditor-button-dropdown">' . t('Styles') . '<span class="ckeditor-button-arrow"></span></span></a>',
       ),
     );
   }
diff --git a/core/modules/ckeditor/src/Tests/CKEditorLanguageDirectionTest.php b/core/modules/ckeditor/src/Tests/CKEditorLanguageDirectionTest.php
index 99999d4..53126e6 100644
--- a/core/modules/ckeditor/src/Tests/CKEditorLanguageDirectionTest.php
+++ b/core/modules/ckeditor/src/Tests/CKEditorLanguageDirectionTest.php
@@ -68,7 +68,8 @@ public function testLanguageDirectionChange() {
     $edit = array('site_default_language' => 'ar');
     $this->drupalPostForm('admin/config/regional/settings', $edit, t('Save configuration'));
 
-    // Once the default language is changed, go to the tested text format configuration page. 
+    // Once the default language is changed, go to the tested text format
+    // configuration page.
     $this->drupalGet('admin/config/content/formats/manage/full_html');
     $this->assertPattern('|cke_rtl|', 'Correct language direction classes are being added.');
   }
diff --git a/core/modules/ckeditor/templates/ckeditor-settings-toolbar.html.twig b/core/modules/ckeditor/templates/ckeditor-settings-toolbar.html.twig
index cdadccf..f9cd7ee 100644
--- a/core/modules/ckeditor/templates/ckeditor-settings-toolbar.html.twig
+++ b/core/modules/ckeditor/templates/ckeditor-settings-toolbar.html.twig
@@ -3,12 +3,15 @@
  * @file
  * Default theme implementation for the CKEditor settings toolbar.
  *
- * This template uses Twig macro to create the CKEditor buttons.
+ * This template uses Twig macro to generate the HTML for internal buttons
+ * (those included with CKEditor) - we can't use regular image URLs here because
+ * these images are part of a sprite. By generating the correct HTML, we can use
+ * the images in that sprite, just like actual CKEditor instances.
  * @see http://twig.sensiolabs.org/doc/tags/macro.html
  *
  * Available variables:
  * - button: A list containing the CKEditor buttons.
- *   - internal_button: Indentifier of internal button.
+ *   - internal_button: Identifier of internal button.
  *   - is_dropdown: Flag for showing a dropdown type button (Optional). If the
  *     value is true then a dropdown button is generated.
  *   - is_separator: Flag for showing a separator "button" (Optional). If the