public function has($string)
    {
        $lowercase = strtolower($string);

        if (!parent::has($lowercase) && !JFactory::getLanguage()->hasKey($string))
        {
            if (isset($this->_aliases[$lowercase])) {
                $key = $this->_aliases[$lowercase];
            }
            elseif (substr($string, 0, strlen($this->getPrefix())) === $this->getPrefix()) {
                $key = $string;
            } else {
                //Gets a key from the catalogue and prefixes it
                $key = $this->getPrefix().$this->generateKey($string);
            }

            $result = JFactory::getLanguage()->hasKey($key);
        }
        else $result = true;

        return $result;
    }