diff --git a/core/modules/rest/src/Plugin/rest/resource/EntityResource.php b/core/modules/rest/src/Plugin/rest/resource/EntityResource.php
index d60e423..f46fdf6 100644
--- a/core/modules/rest/src/Plugin/rest/resource/EntityResource.php
+++ b/core/modules/rest/src/Plugin/rest/resource/EntityResource.php
@@ -6,11 +6,13 @@
 use Drupal\Component\Plugin\PluginManagerInterface;
 use Drupal\Core\Cache\CacheableResponseInterface;
 use Drupal\Core\Config\Entity\ConfigEntityType;
+use Drupal\Core\Entity\ContentEntityInterface;
 use Drupal\Core\Entity\EntityTypeManagerInterface;
 use Drupal\Core\Entity\FieldableEntityInterface;
 use Drupal\Core\Config\ConfigFactoryInterface;
 use Drupal\Core\Entity\EntityInterface;
 use Drupal\Core\Entity\EntityStorageException;
+use Drupal\migrate_drupal\Plugin\migrate\source\d7\FieldableEntity;
 use Drupal\rest\Plugin\ResourceBase;
 use Drupal\rest\ResourceResponse;
 use Psr\Log\LoggerInterface;
@@ -193,9 +195,9 @@ public function post(EntityInterface $entity = NULL) {
   /**
    * Responds to entity PATCH requests.
    *
-   * @param \Drupal\Core\Entity\EntityInterface $original_entity
+   * @param \Drupal\Core\Entity\ContentEntityInterface $original_entity
    *   The original entity object.
-   * @param \Drupal\Core\Entity\EntityInterface $entity
+   * @param \Drupal\Core\Entity\ContentEntityInterface $entity
    *   The entity.
    *
    * @return \Drupal\rest\ModifiedResourceResponse
@@ -203,7 +205,7 @@ public function post(EntityInterface $entity = NULL) {
    *
    * @throws \Symfony\Component\HttpKernel\Exception\HttpException
    */
-  public function patch(EntityInterface $original_entity, EntityInterface $entity = NULL) {
+  public function patch(ContentEntityInterface $original_entity, ContentEntityInterface $entity = NULL) {
     if ($entity == NULL) {
       throw new BadRequestHttpException('No entity content received.');
     }
@@ -219,49 +221,50 @@ public function patch(EntityInterface $original_entity, EntityInterface $entity
     // Overwrite the received properties.
     $entity_keys = $entity->getEntityType()->getKeys();
     foreach ($entity->_restSubmittedFields as $field_name) {
-      $field = $entity->get($field_name);
+      foreach ($entity->getTranslationLanguages() as $langcode => $language) {
 
-      // Entity key fields need special treatment: together they uniquely
-      // identify the entity. Therefore it does not make sense to modify any of
-      // them. However, rather than throwing an error, we just ignore them as
-      // long as their specified values match their current values.
-      if (in_array($field_name, $entity_keys, TRUE)) {
-        // @todo Work around the wrong assumption that entity keys need special
-        // treatment, when only read-only fields need it.
-        // This will be fixed in https://www.drupal.org/node/2824851.
-        if ($entity->getEntityTypeId() == 'comment' && $field_name == 'status' && !$original_entity->get($field_name)->access('edit')) {
+        if (!$original_entity->hasTranslation($langcode)) {
+          $original_entity->addTranslation($langcode, $original_entity->toArray());
+        }
+
+        $field = $entity->getTranslation($langcode)->get($field_name);
+        // Entity key fields need special treatment: together they uniquely
+        // identify the entity. Therefore it does not make sense to modify any of
+        // them. However, rather than throwing an error, we just ignore them as
+        // long as their specified values match their current values.
+        if (in_array($field_name, $entity_keys, TRUE)) {
+          // @todo Work around the wrong assumption that entity keys need special
+          // treatment, when only read-only fields need it.
+          // This will be fixed in https://www.drupal.org/node/2824851.
+          if ($entity->getEntityTypeId() == 'comment' && $field_name == 'status' && !$original_entity->getTranslation($langcode)->get($field_name)->access('edit')) {
+            throw new AccessDeniedHttpException("Access denied on updating field '$field_name'.");
+          }
+          // Unchanged values for entity keys don't need access checking.
+          if ($original_entity->getTranslation($langcode)->get($field_name)->getValue() === $entity->getTranslation($langcode)->get($field_name)->getValue()) {
+            continue;
+          }
+          // It is not possible to set the language to NULL as it is automatically
+          // re-initialized. As it must not be empty, skip it if it is.
+          elseif (isset($entity_keys['langcode']) && $field_name === $entity_keys['langcode'] && $field->isEmpty()) {
+            continue;
+          }
+        }
+        if (!$original_entity->getTranslation($langcode)->get($field_name)->access('edit')) {
           throw new AccessDeniedHttpException("Access denied on updating field '$field_name'.");
         }
 
-        // Unchanged values for entity keys don't need access checking.
-        if ($original_entity->get($field_name)->getValue() === $entity->get($field_name)->getValue()) {
-          continue;
-        }
-        // It is not possible to set the language to NULL as it is automatically
-        // re-initialized. As it must not be empty, skip it if it is.
-        elseif (isset($entity_keys['langcode']) && $field_name === $entity_keys['langcode'] && $field->isEmpty()) {
-          continue;
-        }
-      }
 
-      if (!$original_entity->get($field_name)->access('edit')) {
-        throw new AccessDeniedHttpException("Access denied on updating field '$field_name'.");
+        $original_entity->getTranslation($langcode)->set($field_name, $field->getValue());
       }
-      $original_entity->set($field_name, $field->getValue());
     }
 
     // Validate the received data before saving.
     $this->validate($original_entity);
-    try {
-      $original_entity->save();
-      $this->logger->notice('Updated entity %type with ID %id.', array('%type' => $original_entity->getEntityTypeId(), '%id' => $original_entity->id()));
+    $original_entity->save();
+    $this->logger->notice('Updated entity %type with ID %id.', array('%type' => $original_entity->getEntityTypeId(), '%id' => $original_entity->id()));
 
-      // Return the updated entity in the response body.
-      return new ModifiedResourceResponse($original_entity, 200);
-    }
-    catch (EntityStorageException $e) {
-      throw new HttpException(500, 'Internal Server Error', $e);
-    }
+    // Return the updated entity in the response body.
+    return new ModifiedResourceResponse($original_entity, 200);
   }
 
   /**
diff --git a/core/modules/rest/src/Plugin/rest/resource/EntityResourceValidationTrait.php b/core/modules/rest/src/Plugin/rest/resource/EntityResourceValidationTrait.php
index 09b4b64..6c51322 100644
--- a/core/modules/rest/src/Plugin/rest/resource/EntityResourceValidationTrait.php
+++ b/core/modules/rest/src/Plugin/rest/resource/EntityResourceValidationTrait.php
@@ -3,7 +3,7 @@
 namespace Drupal\rest\Plugin\rest\resource;
 
 use Drupal\Component\Render\PlainTextOutput;
-use Drupal\Core\Entity\EntityInterface;
+use Drupal\Core\Entity\ContentEntityInterface;
 use Drupal\Core\Entity\FieldableEntityInterface;
 use Symfony\Component\HttpKernel\Exception\UnprocessableEntityHttpException;
 
@@ -13,34 +13,34 @@
  */
 trait EntityResourceValidationTrait {
 
-  /**
+  /**->getTranslation($langcode)
    * Verifies that the whole entity does not violate any validation constraints.
    *
-   * @param \Drupal\Core\Entity\EntityInterface $entity
+   * @param \Drupal\Core\Entity\ContentEntityInterface $entity
    *   The entity to validate.
    *
    * @throws \Symfony\Component\HttpKernel\Exception\UnprocessableEntityHttpException
    *   If validation errors are found.
    */
-  protected function validate(EntityInterface $entity) {
+  protected function validate(ContentEntityInterface $entity) {
     // @todo Remove when https://www.drupal.org/node/2164373 is committed.
     if (!$entity instanceof FieldableEntityInterface) {
       return;
     }
-    $violations = $entity->validate();
-
-    // Remove violations of inaccessible fields as they cannot stem from our
-    // changes.
-    $violations->filterByFieldAccess();
-
-    if ($violations->count() > 0) {
-      $message = "Unprocessable Entity: validation failed.\n";
-      foreach ($violations as $violation) {
-        // We strip every HTML from the error message to have a nicer to read
-        // message on REST responses.
-        $message .= $violation->getPropertyPath() . ': ' . PlainTextOutput::renderFromHtml($violation->getMessage()) . "\n";
+    foreach ($entity->getTranslationLanguages() as $langcode => $language) {
+      $violations = $entity->getTranslation($langcode)->validate();
+      // Remove violations of inaccessible fields as they cannot stem from our
+      // changes.
+      $violations->filterByFieldAccess();
+      if ($violations->count() > 0) {
+        $message = "Unprocessable Entity: validation failed.\n";
+        foreach ($violations as $violation) {
+          // We strip every HTML from the error message to have a nicer to read
+          // message on REST responses.
+          $message .= $violation->getPropertyPath() . ': ' . PlainTextOutput::renderFromHtml($violation->getMessage()) . "\n";
+        }
+        throw new UnprocessableEntityHttpException($message);
       }
-      throw new UnprocessableEntityHttpException($message);
     }
   }