diff -u b/core/modules/language/lib/Drupal/language/LanguageNegotiationMethodBase.php b/core/modules/language/lib/Drupal/language/LanguageNegotiationMethodBase.php
--- b/core/modules/language/lib/Drupal/language/LanguageNegotiationMethodBase.php
+++ b/core/modules/language/lib/Drupal/language/LanguageNegotiationMethodBase.php
@@ -8,7 +8,7 @@
 namespace Drupal\language;
 
 use Drupal\Core\Config\ConfigFactoryInterface;
-use Drupal\Core\Language\LanguageInterface;
+use Drupal\Core\Language\LanguageInterface as CoreLanguageInterface;
 use Drupal\Core\Session\AccountInterface;
 
 /**
@@ -61,7 +61,7 @@
   /**
    * {@inheritdoc}
    */
-  public function persist(LanguageInterface $language) {
+  public function persist(CoreLanguageInterface $language) {
     // Remember the method ID used to detect the language.
     $language->setNegotiationMethodId(static::METHOD_ID);
   }