diff --git a/core/modules/language/src/Plugin/LanguageNegotiation/LanguageNegotiationUrl.php b/core/modules/language/src/Plugin/LanguageNegotiation/LanguageNegotiationUrl.php
index 6ea4aee..8a8d341 100644
--- a/core/modules/language/src/Plugin/LanguageNegotiation/LanguageNegotiationUrl.php
+++ b/core/modules/language/src/Plugin/LanguageNegotiation/LanguageNegotiationUrl.php
@@ -183,7 +183,7 @@ public function processOutbound($path, &$options = array(), Request $request = N
         }
 
         // Add Drupal's subfolder from the base_path if there is one.
-        $options['base_url'] .= rtrim(base_path(), '/');
+        $options['base_url'] .= rtrim($request->getBasePath(), '/');
         if ($cacheable_metadata) {
           $cacheable_metadata->addCacheContexts(['languages:' . LanguageInterface::TYPE_URL, 'url.site']);
         }