PHP: CodeIgniter Language Change

gistfile1

<?php if ( ! defined('BASEPATH')) exit('No direct script access allowed');

class Language extends CI_Controller
{		
	public function __construct()
	{
		parent::__construct();
		
		is_logged_in();
	}
	
	public function index($lang)
	{		
		$this->session->set_userdata('lang', $lang);
		
		$this->load->helper('url');
     	redirect('/admin/page/index/', 'refresh');
	}
}