diff --git a/core/lib/Drupal/Core/Language/LanguageManager.php b/core/lib/Drupal/Core/Language/LanguageManager.php
index c0177df114..980b15c592 100644
--- a/core/lib/Drupal/Core/Language/LanguageManager.php
+++ b/core/lib/Drupal/Core/Language/LanguageManager.php
@@ -262,7 +262,7 @@ public static function getStandardLanguageList() {
       'ga' => ['Irish', 'Gaeilge'],
       'gd' => ['Scots Gaelic', 'Gàidhlig'],
       'gl' => ['Galician', 'Galego'],
-      'gsw-berne' => ['Swiss German', 'Schwyzerdütsch'],
+      'gsw' => ['Swiss German', 'Schwyzerdütsch'],
       'gu' => ['Gujarati', 'ગુજરાતી'],
       'he' => ['Hebrew', /* Left-to-right marker "‭" */ 'עברית', LanguageInterface::DIRECTION_RTL],
       'hi' => ['Hindi', 'हिन्दी'],
diff --git a/core/modules/language/tests/src/Functional/LanguageBreadcrumbTest.php b/core/modules/language/tests/src/Functional/LanguageBreadcrumbTest.php
index 964da0d04b..618065afa4 100644
--- a/core/modules/language/tests/src/Functional/LanguageBreadcrumbTest.php
+++ b/core/modules/language/tests/src/Functional/LanguageBreadcrumbTest.php
@@ -31,7 +31,7 @@ protected function setUp() {
     parent::setUp();
     $this->drupalPlaceBlock('system_breadcrumb_block');
     ConfigurableLanguage::createFromLangcode('de')->save();
-    ConfigurableLanguage::createFromLangcode('gsw-berne')->save();
+    ConfigurableLanguage::createFromLangcode('gsw')->save();
   }
 
   /**
@@ -55,7 +55,7 @@ public function testBreadCrumbs() {
     $breadcrumbs = $page->find('css', '.block-system-breadcrumb-block');
     $this->assertNull($breadcrumbs);
 
-    $this->drupalGet('gsw-berne/user/login');
+    $this->drupalGet('gsw/user/login');
     $breadcrumbs = $page->find('css', '.block-system-breadcrumb-block');
     $this->assertNull($breadcrumbs);
 
diff --git a/core/tests/Drupal/KernelTests/Core/Routing/RouteProviderTest.php b/core/tests/Drupal/KernelTests/Core/Routing/RouteProviderTest.php
index 6daa3964c8..f585edb826 100644
--- a/core/tests/Drupal/KernelTests/Core/Routing/RouteProviderTest.php
+++ b/core/tests/Drupal/KernelTests/Core/Routing/RouteProviderTest.php
@@ -591,7 +591,7 @@ public function testRouteCaching() {
 
     // Test with a different current language by switching out the default
     // language.
-    $swiss = ConfigurableLanguage::createFromLangcode('gsw-berne');
+    $swiss = ConfigurableLanguage::createFromLangcode('gsw');
     $language_manager->reset();
     \Drupal::service('language.default')->set($swiss);
 
@@ -599,7 +599,7 @@ public function testRouteCaching() {
     $request = Request::create($path, 'GET');
     $provider->getRouteCollectionForRequest($request);
 
-    $cache = $this->cache->get('route:[language]=gsw-berne:/path/add-one:');
+    $cache = $this->cache->get('route:[language]=gsw:/path/add-one:');
     $this->assertEquals('/path/add/one', $cache->data['path']);
     $this->assertEquals([], $cache->data['query']);
     $this->assertEquals(3, count($cache->data['routes']));