PHP Function Integer To Alphabet (Indonesia Version)

/**
 * Integer To Alphabet
 * to convert decimal variable to alphabet string
 *
 * @author      Ardi Imawan (ardiimawan@gmail.com)
 * @param       $number int
 * @param       $se boolean
 * @return      string
 **/
public function _integer_to_alphabet($number, $se = false)
{
    if($number == 0) return "NOL";

    $alphabet = "";
    $satuan = array(
        (object)array('digit' => 12, 'alphabet' => 'TRILIUN'),
        (object)array('digit' => 9, 'alphabet' => 'MILYAR'),
        (object)array('digit' => 6, 'alphabet' => 'JUTA'),
        (object)array('digit' => 3, 'alphabet' => 'RIBU'),
        (object)array('digit' => 2, 'alphabet' => 'RATUS')
    );

    if(strlen($number) > 2)
    {
        foreach($satuan as $row)
        {
            // triliun
            if(strlen($number) > $row->digit)
            {
                $_int_temp = (int)substr($number, 0, $row->digit*-1);
                $alphabet .= $this->_integer_to_alphabet($_int_temp, $row->digit == 3  && $_int_temp == 1 || $row->digit == 2) . "$row->alphabet ";
                $number = ((int)substr($number, $row->digit*-1))."";
            }
        }
    }

    // puluhan
    if(strlen($number) > 1)
    {
        $_int_temp = (int)substr($number, 0, -1);
        if($_int_temp == 1 && (int)substr($number, -1) > 0)
        {
            $number = (int)substr($number, -1);
            $alphabet .= $this->_integer_to_alphabet($number, true) . "BELAS ";
            $number = "";
        }
        else
        {
            $alphabet .= $this->_integer_to_alphabet($_int_temp, $_int_temp == 1) . "PULUH ";
            $number = (int)substr($number, -1);
        }

    }
    // satuan
    if($se && $number == 1) $alphabet .= "SE";
    else if($number == 1) $alphabet .= "SATU ";
    else if($number == 2) $alphabet .= "DUA ";
    else if($number == 3) $alphabet .= "TIGA ";
    else if($number == 4) $alphabet .= "EMPAT ";
    else if($number == 5) $alphabet .= "LIMA ";
    else if($number == 6) $alphabet .= "ENAM ";
    else if($number == 7) $alphabet .= "TUJUH ";
    else if($number == 8) $alphabet .= "DELAPAN ";
    else if($number == 9) $alphabet .= "SEMBILAN ";

    return $alphabet;
}