diff --git a/core/lib/Drupal/Core/Entity/EntityManager.php b/core/lib/Drupal/Core/Entity/EntityManager.php
index bcf0f3d..633291a 100644
--- a/core/lib/Drupal/Core/Entity/EntityManager.php
+++ b/core/lib/Drupal/Core/Entity/EntityManager.php
@@ -499,12 +499,15 @@ public function getFieldDefinitions($entity_type, $bundle = NULL) {
         // Enforce fields to be multiple and untranslatable by default.
         $entity_info = $this->getDefinition($entity_type);
         $keys = array_intersect_key(array_filter($entity_info['entity_keys']), array_flip(array('id', 'revision', 'uuid', 'bundle')));
-        $base_fields = array_flip(array('langcode') + $keys);
+        $untranslatable_fields = array_flip(array('langcode') + $keys);
         foreach (array('definitions', 'optional') as $key) {
           foreach ($this->entityFieldInfo[$entity_type][$key] as $name => &$definition) {
             $definition['list'] = TRUE;
-            // Ensure base fields are never made translatable.
-            if (isset($base_fields[$name]) || !isset($definition['translatable'])) {
+            // Ensure ids and langcode fields are never made translatable.
+            if (isset($untranslatable_fields[$name]) && !empty($definition['translatable'])) {
+              throw new \LogicException(format_string('The @field field cannot be translatable.', array('@field' => $definition['label'])));
+            }
+            if (!isset($definition['translatable'])) {
               $definition['translatable'] = FALSE;
             }
           }
diff --git a/core/modules/system/lib/Drupal/system/Tests/Entity/EntityTranslationTest.php b/core/modules/system/lib/Drupal/system/Tests/Entity/EntityTranslationTest.php
index 5e663ca..38e4c23 100644
--- a/core/modules/system/lib/Drupal/system/Tests/Entity/EntityTranslationTest.php
+++ b/core/modules/system/lib/Drupal/system/Tests/Entity/EntityTranslationTest.php
@@ -9,6 +9,7 @@
 
 use Drupal\Core\Language\Language;
 use Drupal\Core\TypedData\TranslatableInterface;
+use Drupal\entity_test\Entity\EntityTestMulRev;
 
 /**
  * Tests entity translation.
@@ -491,4 +492,42 @@ function testEntityTranslationAPI() {
     $this->assertEqual($field->getLangcode(), $langcode2, 'Field object has the expected langcode.');
   }
 
+  /**
+   * Check that field translatability is handled properly.
+   */
+  function testFieldDefinitions() {
+    // Check that field translatability can be altered to be enabled or disabled
+    // in field definitions.
+    $entity_type = 'entity_test_mulrev';
+    $this->state->set('entity_test.field_definitions.translatable', array('name' => FALSE));
+    $this->entityManager->clearCachedFieldDefinitions();
+    $definitions = $this->entityManager->getFieldDefinitions($entity_type);
+    $this->assertFalse($definitions['name']['translatable'], 'Field translatability can be disabled programmatically.');
+
+    $this->state->set('entity_test.field_definitions.translatable', array('name' => TRUE));
+    $this->entityManager->clearCachedFieldDefinitions();
+    $definitions = $this->entityManager->getFieldDefinitions($entity_type);
+    $this->assertTrue($definitions['name']['translatable'], 'Field translatability can be enabled programmatically.');
+
+    // Check that field translatability is disabled by default.
+    $base_field_definitions = EntityTestMulRev::baseFieldDefinitions($entity_type);
+    $this->assertTrue(!isset($base_field_definitions['id']['translatable']), 'Translatability for the <em>id</em> field is not defined.');
+    $this->assertFalse($definitions['id']['translatable'], 'Field translatability is disabled by default.');
+
+    // Check that entity ids and langcode fields cannot be translatable.
+    foreach (array('id', 'uuid', 'revision_id', 'type', 'langcode') as $name) {
+      $this->state->set('entity_test.field_definitions.translatable', array($name => TRUE));
+      $this->entityManager->clearCachedFieldDefinitions();
+      $message = format_string('Field %field cannot be translatable.', array('%field' => $name));
+
+      try {
+        $definitions = $this->entityManager->getFieldDefinitions($entity_type);
+        $this->fail($message);
+      }
+      catch (\LogicException $e) {
+        $this->pass($message);
+      }
+    }
+  }
+
 }
diff --git a/core/modules/system/tests/modules/entity_test/entity_test.module b/core/modules/system/tests/modules/entity_test/entity_test.module
index cc8800e..e949e50 100644
--- a/core/modules/system/tests/modules/entity_test/entity_test.module
+++ b/core/modules/system/tests/modules/entity_test/entity_test.module
@@ -73,6 +73,17 @@ function entity_test_entity_info_alter(&$info) {
 }
 
 /**
+ * Implements hook_entity_field_info_alter().
+ */
+function entity_test_entity_field_info_alter(&$info, $entity_type) {
+  if ($entity_type == 'entity_test_mulrev' && ($names = \Drupal::state()->get('entity_test.field_definitions.translatable'))) {
+    foreach ($names as $name => $value) {
+      $info['definitions'][$name]['translatable'] = $value;
+    }
+  }
+}
+
+/**
  * Creates a new bundle for entity_test entities.
  *
  * @param string $bundle