diff --git a/core/modules/language/lib/Drupal/language/Entity/Language.php b/core/modules/language/lib/Drupal/language/Entity/Language.php
index 0423657..6f3f6ac 100644
--- a/core/modules/language/lib/Drupal/language/Entity/Language.php
+++ b/core/modules/language/lib/Drupal/language/Entity/Language.php
@@ -95,9 +95,12 @@ class Language extends ConfigEntityBase implements LanguageInterface {
   /**
    * Used to detect when the site becomes multilingual.
    *
+   * This property is not saved to the language entity, but is needed for
+   * detecting when to rebuild the services.
+   *
    * @var bool
    */
-  protected $multilingual;
+  protected $preSaveMultilingual;
 
   /**
    * Sets the default flag on the language entity.
@@ -149,7 +152,7 @@ public function postSave(EntityStorageInterface $storage, $update = TRUE) {
 
     // If after adding this language the site will become multilingual, we need to
     // rebuild language services.
-    if (!$this->multilingual && !$update) {
+    if (!$this->preSaveMultilingual && !$update) {
       ConfigurableLanguageManager::rebuildServices();
     }
   }