diff --git a/core/modules/language/language.admin.inc b/core/modules/language/language.admin.inc
index 3bd73f9..d4b0971 100644
--- a/core/modules/language/language.admin.inc
+++ b/core/modules/language/language.admin.inc
@@ -273,7 +273,7 @@ function template_preprocess_language_content_settings_table(&$variables) {
           'data' => array(
             '#prefix' => '<label>',
             '#suffix' => '</label>',
-            '#markup' => check_plain($element[$bundle]['settings']['#label']),
+            '#markup' => \Drupal\Component\Utility\String::checkPlain($element[$bundle]['settings']['#label']),
           ),
           'class' => array('bundle'),
         ),
diff --git a/core/modules/language/lib/Drupal/language/Form/LanguageFormBase.php b/core/modules/language/lib/Drupal/language/Form/LanguageFormBase.php
index b2adf0a..8bd987f 100644
--- a/core/modules/language/lib/Drupal/language/Form/LanguageFormBase.php
+++ b/core/modules/language/lib/Drupal/language/Form/LanguageFormBase.php
@@ -72,7 +72,7 @@ public function validateCommon(array $form, array &$form_state) {
     if (!isset($form['langcode_view']) && preg_match('@[^a-zA-Z_-]@', $form_state['values']['langcode'])) {
       $this->setFormError('langcode', $form_state, $this->t('%field may only contain characters a-z, underscores, or hyphens.', array('%field' => $form['langcode']['#title'])));
     }
-    if ($form_state['values']['name'] != check_plain($form_state['values']['name'])) {
+    if ($form_state['values']['name'] != \Drupal\Component\Utility\String::checkPlain($form_state['values']['name'])) {
       $this->setFormError('name', $form_state, $this->t('%field cannot contain any markup.', array('%field' => $form['name']['#title'])));
     }
   }