diff --git a/core/lib/Drupal/Core/Entity/ContentEntityForm.php b/core/lib/Drupal/Core/Entity/ContentEntityForm.php
index 55fb564..d965ebb 100644
--- a/core/lib/Drupal/Core/Entity/ContentEntityForm.php
+++ b/core/lib/Drupal/Core/Entity/ContentEntityForm.php
@@ -145,8 +145,11 @@ protected function updateFormLangcode(FormStateInterface $form_state) {
     // Update the form language as it might have changed.
     // @todo This should use an entity key for the entity language.
     if ($form_state->hasValue('langcode') && $this->isDefaultFormLangcode($form_state)) {
-      $item = $form_state->getValue('langcode');
-      $form_state->set('langcode', $item[0]['value']);
+      $langcode = $form_state->getValue('langcode');
+      if (is_array($langcode)) {
+        $langcode = isset($langcode[0]['value']) ? $langcode[0]['value'] : NULL;
+      }
+      $form_state->set('langcode', $langcode);
     }
   }