diff --git a/core/modules/comment/tests/src/Functional/CommentLanguageTest.php b/core/modules/comment/tests/src/Functional/CommentLanguageTest.php
index 213e4e04211..5da8ea42e10 100644
--- a/core/modules/comment/tests/src/Functional/CommentLanguageTest.php
+++ b/core/modules/comment/tests/src/Functional/CommentLanguageTest.php
@@ -73,7 +73,7 @@ class CommentLanguageTest extends BrowserTestBase {
     $this->submitForm($edit, 'Save');
 
     // Enable content language negotiation UI.
-    \Drupal::state()->set('language_test.content_language_type', TRUE);
+    \Drupal::keyValue('language_test')->set('content_language_type', TRUE);
 
     // Set interface language detection to user and content language detection
     // to URL. Disable inheritance from interface language to ensure content
diff --git a/core/modules/language/tests/language_test/language_test.module b/core/modules/language/tests/language_test/language_test.module
index dc5e63a4e61..3ef6906d987 100644
--- a/core/modules/language/tests/language_test/language_test.module
+++ b/core/modules/language/tests/language_test/language_test.module
@@ -23,7 +23,7 @@ function language_test_page_top() {
  * Implements hook_language_types_info().
  */
 function language_test_language_types_info() {
-  if (\Drupal::state()->get('language_test.language_types')) {
+  if (\Drupal::keyValue('language_test')->get('language_types')) {
     return [
       'test_language_type' => [
         'name' => t('Test'),
@@ -41,7 +41,7 @@ function language_test_language_types_info() {
  * Implements hook_language_types_info_alter().
  */
 function language_test_language_types_info_alter(array &$language_types) {
-  if (\Drupal::state()->get('language_test.content_language_type')) {
+  if (\Drupal::keyValue('language_test')->get('content_language_type')) {
     $language_types[LanguageInterface::TYPE_CONTENT]['locked'] = FALSE;
     unset($language_types[LanguageInterface::TYPE_CONTENT]['fixed']);
     // By default languages are not configurable. Make
@@ -59,7 +59,7 @@ function language_test_language_types_info_alter(array &$language_types) {
  * Implements hook_language_negotiation_info_alter().
  */
 function language_test_language_negotiation_info_alter(array &$negotiation_info) {
-  if (\Drupal::state()->get('language_test.language_negotiation_info_alter')) {
+  if (\Drupal::keyValue('language_test')->get('language_negotiation_info_alter')) {
     unset($negotiation_info[LanguageNegotiationUI::METHOD_ID]);
   }
 }
diff --git a/core/modules/language/tests/src/Functional/LanguageNegotiationInfoTest.php b/core/modules/language/tests/src/Functional/LanguageNegotiationInfoTest.php
index de45e2c68d8..6228a9b8562 100644
--- a/core/modules/language/tests/src/Functional/LanguageNegotiationInfoTest.php
+++ b/core/modules/language/tests/src/Functional/LanguageNegotiationInfoTest.php
@@ -51,18 +51,18 @@ class LanguageNegotiationInfoTest extends BrowserTestBase {
   }
 
   /**
-   * Sets state flags for language_test module.
+   * Sets key/value pairs for language_test module.
    *
    * Ensures to correctly update data both in the child site and the test runner
    * environment.
    *
    * @param array $values
-   *   The key/value pairs to set in state.
+   *   The key/value pairs to set in the key value store.
    */
-  protected function stateSet(array $values) {
-    // Set the new state values.
-    $this->container->get('state')->setMultiple($values);
-    // Refresh in-memory static state/config caches and static variables.
+  protected function keysValuesSet(array $values): void {
+    // Set the new key value values.
+    $this->container->get('keyvalue')->get('language_test')->setMultiple($values);
+    // Refresh in-memory static key value/config caches and static variables.
     $this->refreshVariables();
     // Refresh/rewrite language negotiation configuration, in order to pick up
     // the manipulations performed by language_test module's info alter hooks.
@@ -73,13 +73,13 @@ class LanguageNegotiationInfoTest extends BrowserTestBase {
    * Tests alterations to language types/negotiation info.
    */
   public function testInfoAlterations(): void {
-    $this->stateSet([
+    $this->keysValuesSet([
       // Enable language_test type info.
-      'language_test.language_types' => TRUE,
+      'language_types' => TRUE,
       // Enable language_test negotiation info (not altered yet).
-      'language_test.language_negotiation_info' => TRUE,
+      'language_negotiation_info' => TRUE,
       // Alter LanguageInterface::TYPE_CONTENT to be configurable.
-      'language_test.content_language_type' => TRUE,
+      'content_language_type' => TRUE,
     ]);
     $this->container->get('module_installer')->install(['language_test']);
     $this->resetAll();
@@ -109,8 +109,8 @@ class LanguageNegotiationInfoTest extends BrowserTestBase {
 
     // Alter language negotiation info to remove interface language negotiation
     // method.
-    $this->stateSet([
-      'language_test.language_negotiation_info_alter' => TRUE,
+    $this->keysValuesSet([
+      'language_negotiation_info_alter' => TRUE,
     ]);
 
     $negotiation = $this->config('language.types')->get('negotiation.' . $type . '.enabled');