--- /dev/null
+<?php
+
+namespace Drupal\language;
+
+use Drupal\Core\Url;
+use Symfony\Component\HttpFoundation\Request;
+
+/**
+ * Interface for language switcher classes.
+ */
+interface LanguageSwitcherInterface {
+
+ /**
+ * Returns language switch links.
+ *
+ * @param \Symfony\Component\HttpFoundation\Request $request
+ * The current request.
+ * @param string $type
+ * The language type.
+ * @param \Drupal\Core\Url $url
+ * The URL the switch links will be relative to.
+ *
+ * @return array
+ * An array of link arrays keyed by language code.
+ */
+ public function getLanguageSwitchLinks(Request $request, $type, Url $url);
+
+}