protected static function readDirectory($directory)
 {
     if (!empty(self::$cache)) {
         return self::$cache;
     }
     $langs = array();
     if ($handle = opendir($directory)) {
         while ($lang = readdir($handle)) {
             if (strpos($lang, ".php") !== false) {
                 $langKey = str_replace('.php', '', $lang);
                 $langs[$langKey] = (include $directory . '/' . $lang);
             }
         }
         closedir($handle);
     }
     self::$cache = $langs;
     return $langs;
 }