diff --git a/core/lib/Drupal/Core/Routing/CachedUrlGenerator.php b/core/lib/Drupal/Core/Routing/CachedUrlGenerator.php
index cd8421c..8eade10 100644
--- a/core/lib/Drupal/Core/Routing/CachedUrlGenerator.php
+++ b/core/lib/Drupal/Core/Routing/CachedUrlGenerator.php
@@ -198,7 +198,7 @@ public function fromRequestStack(RequestStack $requestStack) {
     }
     // Only multilingual sites have language dependant URLs.
     if ($this->languageManager->isMultilingual()) {
-      $this->cacheKey .= '::' . $this->languageManager->getCurrentLanguage(Language::TYPE_URL)->id;
+      $this->cacheKey .= '::' . $this->languageManager->getCurrentLanguage(Language::TYPE_URL)->getId();
     }
     $cached = $this->cache->get($this->cacheKey);
     if ($cached) {