diff --git a/core/lib/Drupal/Core/EventSubscriber/LanguageRequestSubscriber.php b/core/lib/Drupal/Core/EventSubscriber/LanguageRequestSubscriber.php
index 0969223..9a05a28 100644
--- a/core/lib/Drupal/Core/EventSubscriber/LanguageRequestSubscriber.php
+++ b/core/lib/Drupal/Core/EventSubscriber/LanguageRequestSubscriber.php
@@ -14,7 +14,7 @@
 use Symfony\Component\EventDispatcher\EventSubscriberInterface;
 
 /**
- * Sets the $request proprerty on the language manager.
+ * Sets the $request property on the language manager.
  */
 class LanguageRequestSubscriber implements EventSubscriberInterface {
 
diff --git a/core/modules/language/language.negotiation.inc b/core/modules/language/language.negotiation.inc
index ce0f1dc..280caf9 100644
--- a/core/modules/language/language.negotiation.inc
+++ b/core/modules/language/language.negotiation.inc
@@ -1,5 +1,7 @@
 <?php
 
+use \Symfony\Component\HttpFoundation\Request;
+
 /**
  * @file
  * Language negotiation functions.
@@ -213,7 +215,7 @@ function language_from_user($languages) {
  * @return
  *   A valid language code on success, FALSE otherwise.
  */
-function language_from_user_admin(array $languages, \Symfony\Component\HttpFoundation\Request $request = NULL) {
+function language_from_user_admin(array $languages, Request $request = NULL) {
   // User preference (only for authenticated users).
   global $user;
 
@@ -262,16 +264,16 @@ function language_from_session($languages) {
  * @param $languages
  *   An array of valid language objects.
  *
- * @param $request
- *   The HttpRequest object representing the current request.
+ * @param \Symfony\Component\HttpFoundation\Request|null $request
+ *   (optional) The HttpRequest object representing the current request.
  *
  * @return
  *   A valid language code on success, FALSE otherwise.
  */
-function language_from_url($languages, $request) {
+function language_from_url($languages, Request $request = NULL) {
   $language_url = FALSE;
 
-  if (!language_negotiation_method_enabled(LANGUAGE_NEGOTIATION_URL)) {
+  if (!language_negotiation_method_enabled(LANGUAGE_NEGOTIATION_URL) || !$request) {
     return $language_url;
   }
 
@@ -281,7 +283,8 @@ function language_from_url($languages, $request) {
       $request_path = urldecode(trim($request->getPathInfo(), '/'));
 
       list($language, $path) = language_url_split_prefix($request_path, $languages);
-      // Store the correct system path, i.e., minus the path prefix.
+      // Store the correct system path, i.e., the request path without the
+      // language prefix.
       _language_resolved_path($path);
 
       if ($language !== FALSE) {