correct url() request I need to make a redirect after a customer added something to his cart so I write this: 

function MODULE_form_alter(&amp;$form, &amp;$form_state, $form_id) {
  array_push($form['#submit'], '_MODULE_redirect_to_products');
}

function  _MODULE_redirect_to_products(&amp;$form, &amp;$form_state){
  global $language ;

  $form_state['redirect'] = url('prodotti', array('language' =&gt; $language));
}


but this code redirect me to  

/dev/azzurra/?q=it//dev/azzurra/%3Fq%3Dit/prodotti


but I need to redirect to

/dev/azzurra/?q=it/prodotti


according to the language obviously.

UPDATE:
I'm try to use 

 $form_state['redirect']


but if I display this field before modify it I can see this 

Array
(
    [0] =&gt; prodotti
    [1] =&gt; Array
        (
            [language] =&gt; stdClass Object
                (
                    [language] =&gt; it
                    [name] =&gt; Italian
                    [native] =&gt; Italiano
                    [direction] =&gt; 0
                    [enabled] =&gt; 1
                    [plurals] =&gt; 2
                    [formula] =&gt; ($n!=1)
                    [domain] =&gt; 
                    [prefix] =&gt; it
                    [weight] =&gt; 0
                    [javascript] =&gt; a97-0F_JBbaSYaN4XQBbFbhCLCysRpSabTcDmQjB73E
                    [provider] =&gt; locale-url
                )

        )

    [2] =&gt; 302
)


but the form redirect me to 'it/testate/name' because the form 'add product' is displayed in a view so I think that the views module override the $form_state['redirect'] after me so the default redirect [and mine one..].   

I think I can't use this kind of redirect.. 
How can I achieve this redirect correctly?
$form_state['redirect'] does not take full URL. It takes the same set of parameters url() does. In your case it should probably look like this:

$form_state['redirect'] = array(
  // $path
  'prodotti',
  // $options
  array('language' =&gt; $language),
  // $http_response_code
  302,
);