diff --git a/core/modules/system/system.module b/core/modules/system/system.module
index ce1b39b..6d35954 100644
--- a/core/modules/system/system.module
+++ b/core/modules/system/system.module
@@ -2312,6 +2312,11 @@ function system_data_type_info() {
       'description' => t('An entity field referencing a language.'),
       'class' => '\Drupal\Core\Entity\Field\Type\LanguageItem',
       'list class' => '\Drupal\Core\Entity\Field\Type\Field',
+      'constraints' => array(
+        'ComplexData' => array(
+          'value' => array('Length' => array('max' => 12)),
+        ),
+      ),
     ),
     'entity_reference_field' => array(
       'label' => t('Entity reference field item'),
diff --git a/core/modules/system/tests/modules/entity_test/lib/Drupal/entity_test/EntityTestStorageController.php b/core/modules/system/tests/modules/entity_test/lib/Drupal/entity_test/EntityTestStorageController.php
index 2cf25ec..1d2b879 100644
--- a/core/modules/system/tests/modules/entity_test/lib/Drupal/entity_test/EntityTestStorageController.php
+++ b/core/modules/system/tests/modules/entity_test/lib/Drupal/entity_test/EntityTestStorageController.php
@@ -49,9 +49,6 @@ public function baseFieldDefinitions() {
       'label' => t('Language code'),
       'description' => t('The language code of the test entity.'),
       'type' => 'language_field',
-      'property_constraints' => array(
-        'value' => array('Length' => array('max' => 12)),
-      ),
     );
     $fields['name'] = array(
       'label' => t('Name'),