public function getLangClient() {
        if (!array_key_exists('HTTP_ACCEPT_LANGUAGE', $_SERVER) || !$_SERVER['HTTP_ACCEPT_LANGUAGE']) {
            return Config::config()['user']['output']['lang'];
        }
        else {
            $langcode = (!empty($_SERVER['HTTP_ACCEPT_LANGUAGE'])) ? $_SERVER['HTTP_ACCEPT_LANGUAGE'] : '';
            $langcode = (!empty($langcode)) ? explode(";", $langcode) : $langcode;
            $langcode = (!empty($langcode['0'])) ? explode(",", $langcode['0']) : $langcode;
            $langcode = (!empty($langcode['0'])) ? explode("-", $langcode['0']) : $langcode;

            return $langcode['0'];
        }
    }