The URL language provider configuration form.
function locale_language_providers_session_form($form, &$form_state) {
$form['locale_language_negotiation_session_param'] = array(
'#title' => t('Request/session parameter'),
'#type' => 'textfield',
'#default_value' => variable_get('locale_language_negotiation_session_param', 'language'),
'#description' => t('Name of the request/session parameter used to determine the desired language.'),
);
$form_state['redirect'] = 'admin/config/regional/language/configure';
return system_settings_form($form);
}