diff --git a/core/lib/Drupal/Core/Entity/EntityFormController.php b/core/lib/Drupal/Core/Entity/EntityFormController.php
index 4a03975..6d2c9fb 100644
--- a/core/lib/Drupal/Core/Entity/EntityFormController.php
+++ b/core/lib/Drupal/Core/Entity/EntityFormController.php
@@ -80,6 +80,15 @@ public function form(array $form, array &$form_state, EntityInterface $entity) {
     if (!empty($info['fieldable'])) {
       field_attach_form($entity, $form, $form_state, $this->getFormLangcode($form_state));
     }
+    if (!isset($form['langcode'])) {
+      // If the form did not specify otherwise, default to keeping the existing
+      // language of the entity or defaulting to the site default language for
+      // new entities.
+      $form['langcode'] = array(
+        '#type' => 'value',
+        '#value' => !$entity->isNew() ? $entity->langcode : language_default()->langcode,
+      );
+    }
     return $form;
   }
 
diff --git a/core/modules/block/custom_block/config/custom_block.type.basic.yml b/core/modules/block/custom_block/config/custom_block.type.basic.yml
index 1b0e2f8..58e87d7 100644
--- a/core/modules/block/custom_block/config/custom_block.type.basic.yml
+++ b/core/modules/block/custom_block/config/custom_block.type.basic.yml
@@ -2,3 +2,4 @@ id: basic
 label: Basic block
 revision: '0'
 description: A basic block contains a title and a body.
+langcode: en
diff --git a/core/modules/contact/config/contact.category.feedback.yml b/core/modules/contact/config/contact.category.feedback.yml
index 8aff8c6..aae9098 100644
--- a/core/modules/contact/config/contact.category.feedback.yml
+++ b/core/modules/contact/config/contact.category.feedback.yml
@@ -3,3 +3,4 @@ label: 'Website feedback'
 recipients: []
 reply: ''
 weight: '0'
+langcode: en
diff --git a/core/modules/filter/filter.admin.inc b/core/modules/filter/filter.admin.inc
index 806c1d7..246f286 100644
--- a/core/modules/filter/filter.admin.inc
+++ b/core/modules/filter/filter.admin.inc
@@ -169,6 +169,11 @@ function filter_admin_format_form($form, &$form_state, $format) {
     '#disabled' => !empty($format->format),
     '#weight' => -20,
   );
+  // @todo Remove once moved to FilterFormatFormController.
+  $form['langcode'] = array(
+    '#type' => 'value',
+    '#value' => !$format->isNew() ? $format->langcode : language_default()->langcode,
+  );
 
   // Add user role access selection.
   $form['roles'] = array(
diff --git a/core/modules/user/config/user.role.anonymous.yml b/core/modules/user/config/user.role.anonymous.yml
index 11defb0..1947f35 100644
--- a/core/modules/user/config/user.role.anonymous.yml
+++ b/core/modules/user/config/user.role.anonymous.yml
@@ -1,3 +1,4 @@
 id: anonymous
 label: Anonymous user
 weight: 0
+langcode: en
diff --git a/core/modules/user/config/user.role.authenticated.yml b/core/modules/user/config/user.role.authenticated.yml
index dc4b65d..16df96d 100644
--- a/core/modules/user/config/user.role.authenticated.yml
+++ b/core/modules/user/config/user.role.authenticated.yml
@@ -1,3 +1,4 @@
 id: authenticated
 label: Authenticated user
 weight: 1
+langcode: en
diff --git a/core/modules/user/user.admin.inc b/core/modules/user/user.admin.inc
index c3931d8..882cef2 100644
--- a/core/modules/user/user.admin.inc
+++ b/core/modules/user/user.admin.inc
@@ -1004,6 +1004,11 @@ function user_admin_role($form, $form_state, $role) {
       'source' => array('role', 'label'),
     ),
   );
+  // @todo Remove once moved to RoleFormController.
+  $form['role']['langcode'] = array(
+    '#type' => 'value',
+    '#value' => !$role->isNew() ? $role->langcode : language_default()->langcode,
+  );
   $form['role']['weight'] = array(
     '#type' => 'value',
     '#value' => $role->weight,