diff --git a/core/modules/language/lib/Drupal/language/Plugin/Block/LanguageBlock.php b/core/modules/language/lib/Drupal/language/Plugin/Block/LanguageBlock.php
index 5279dd6..d5a1c05 100644
--- a/core/modules/language/lib/Drupal/language/Plugin/Block/LanguageBlock.php
+++ b/core/modules/language/lib/Drupal/language/Plugin/Block/LanguageBlock.php
@@ -52,4 +52,20 @@ public function build() {
     return $build;
   }
 
+  /**
+   * {@inheritdoc}
+   */
+  public function blockForm($form, &$form_state) {
+    $form = parent::blockForm($form, $form_state);
+    $path = drupal_is_front_page() ? '<front>' : current_path();
+    list(, $type) = explode(':', $this->getPluginId());
+    $links = language_negotiation_get_switch_links($type, $path);
+    // Warn the user that if there are no links to show, the block won't appear.
+    if (empty($links)) {
+      drupal_set_message($this->t('You do not have any language detection method enabled that provide URL based detection. The language switcher module will not be shown.'), 'warning');
+    }
+
+    return $form;
+  }
+
 }