class Controller_Welcome extends Controller {

    public function action_index()
    {
        echo self::lang("Hi I'm using :framework, because I'm :hyperbool", array('framework'=>'Fuel', 'hyperbool'=>'awesome'));

    }

    static function lang($string, $array)
    {
    {
        $key = array_keys($array);
        $value = array_values($array);
        return str_replace($key, $value, $string);
    }
    }