diff --git a/core/modules/language/language.negotiation.inc b/core/modules/language/language.negotiation.inc
index 2182f4d..92c6284 100644
--- a/core/modules/language/language.negotiation.inc
+++ b/core/modules/language/language.negotiation.inc
@@ -462,9 +462,10 @@ function language_url_rewrite_url(&$path, &$options) {
           }
 
           // Ask for an absolute URL with our modified base URL.
+          // We also add Drupal's subfolder from the base_path if there is one.
           $url_scheme = Drupal::request()->isSecure() ? 'https://' : 'http://';
           $options['absolute'] = TRUE;
-          $options['base_url'] = $url_scheme . $domains[$options['language']->langcode];
+          $options['base_url'] = $url_scheme . $domains[$options['language']->langcode] . rtrim(base_path(), '/');
 
           // In case either the original base URL or the HTTP host contains a
           // port, retain it.