public static function getDefaultLanguage()
    {
        if (null === self::$defaultLanguage) {
            self::$defaultLanguage = LangQuery::create()->findOneByByDefault(1);

            if (null === self::$defaultLanguage) {
                throw new \RuntimeException("No default language is defined. Please define one.");
            }
        }

        return self::$defaultLanguage;
    }