diff --git a/core/modules/comment/comment.module b/core/modules/comment/comment.module
index 7c7c7ed..deb1ff4 100644
--- a/core/modules/comment/comment.module
+++ b/core/modules/comment/comment.module
@@ -1025,7 +1025,7 @@ function comment_view_multiple($comments, $view_mode = 'full', $langcode = NULL)
 function comment_form_field_ui_field_instance_edit_form_alter(&$form, $form_state) {
   if ($form['#field']['type'] == 'comment') {
     // Collect translation settings.
-    if (module_exists('translation_entity')) {
+    if (module_exists('content_translation')) {
       array_unshift($form['#submit'], 'comment_translation_configuration_element_submit');
     }
 
@@ -2029,12 +2029,12 @@ function _comment_field_instance_settings_form_process($element, $form_state) {
   array_pop($parents);
   $element['#parents'] = $parents;
   // Add translation entity handlers.
-  if (Drupal::moduleHandler()->moduleExists('translation_entity')) {
+  if (Drupal::moduleHandler()->moduleExists('content_translation')) {
     $comment_form = $element;
-    $comment_form_state['translation_entity']['key'] = 'language_configuration';
-    $element += translation_entity_enable_widget('comment', $element['#field_name'], $comment_form, $comment_form_state);
-    $element['translation_entity']['#parents'] = $element['translation_entity']['#array_parents'] = array(
-      'translation_entity'
+    $comment_form_state['content_translation']['key'] = 'language_configuration';
+    $element += content_translation_enable_widget('comment', $element['#field_name'], $comment_form, $comment_form_state);
+    $element['content_translation']['#parents'] = $element['content_translation']['#array_parents'] = array(
+      'content_translation'
     );
   }
   return $element;
diff --git a/core/modules/comment/lib/Drupal/comment/Plugin/field/field_type/CommentItem.php b/core/modules/comment/lib/Drupal/comment/Plugin/field/field_type/CommentItem.php
index 4a21bba..611c480 100644
--- a/core/modules/comment/lib/Drupal/comment/Plugin/field/field_type/CommentItem.php
+++ b/core/modules/comment/lib/Drupal/comment/Plugin/field/field_type/CommentItem.php
@@ -148,7 +148,9 @@ public function instanceSettingsForm(array $form, array &$form_state) {
    * {@inheritdoc}
    */
   public function applyDefaultValue($notify = TRUE) {
-    $this->setValue($this->getInstance()->default_value, $notify);
+    // Retrieve the configured default value for the instance. The configured
+    $defaults = $this->getInstance()->default_value;
+    $this->setValue(reset($defaults), $notify);
     return $this;
   }
 
diff --git a/core/modules/comment/lib/Drupal/comment/Tests/CommentTranslationUITest.php b/core/modules/comment/lib/Drupal/comment/Tests/CommentTranslationUITest.php
index 7789b49..6c952de 100644
--- a/core/modules/comment/lib/Drupal/comment/Tests/CommentTranslationUITest.php
+++ b/core/modules/comment/lib/Drupal/comment/Tests/CommentTranslationUITest.php
@@ -54,7 +54,7 @@ function setupBundle() {
     // Add another comment field with new bundle to page content type.
     comment_add_default_comment_field('node', 'page');
     // Mark this bundle as translatable.
-    translation_entity_set_config('comment', 'comment_article', 'enabled', TRUE);
+    content_translation_set_config('comment', 'comment_article', 'enabled', TRUE);
     // Refresh entity info.
     entity_info_cache_clear();
     // Flush the permissions after adding the translatable comment bundle.