"Language" setting is not saved

Hi,
by dumping (using dpm() of devel module) the content of $form, $form_state, $account_form, $account, $account_form_state I discovered that the value of the "Language" set by user during the editing of the user profile form is lost during the "submit" phase taking to a NULL Language.

A confirmation of this behaviour can be obtained by editing the user profile by hand, going to user/uid/edit which, instead is working correctly.

My quick and dirty fix is the following:

in account_profile.module

add this:

    // If selected language is not empty
    if($form_state['clicked_button']['#post']['language']){
        // We set manually the corresponding Language value
        $account_form_state['language']=$form_state['clicked_button']['#post']['language'];        
    }

before this line

user_save($account, $account_form_state, $category);

It was just a deduction from analyzing the data passed through the various functions I am not stating is the best or the most appropriate way to do this.

Any better suggestion is warmly welcome.

Thanks.

AM