--- /dev/null
+<?php
+
+namespace Drupal\language\Plugin\LanguageNegotiation;
+
+use Drupal\language\LanguageNegotiationMethodBase;
+use Symfony\Component\HttpFoundation\Request;
+
+/**
+ * Identifies the language from the interface text language selected for page.
+ *
+ * @LanguageNegotiation(
+ * id = Drupal\language\Plugin\LanguageNegotiation\LanguageNegotiationUI::METHOD_ID,
+ * types = {Drupal\Core\Language\LanguageInterface::TYPE_CONTENT},
+ * weight = 9,
+ * name = @Translation("Interface"),
+ * description = @Translation("Use the detected interface language.")
+ * )
+ */
+class LanguageNegotiationUI extends LanguageNegotiationMethodBase {
+
+ /**
+ * The language negotiation method id.
+ */
+ const METHOD_ID = 'language-interface';
+
+ /**
+ * {@inheritdoc}
+ */
+ public function getLangcode(Request $request = NULL) {
+ return $this->languageManager ? $this->languageManager->getCurrentLanguage()->getId() : NULL;
+ }
+
+}