Builds the session language negotiation method configuration form.
language_negotiation_configure_session_form_submit()
function language_negotiation_configure_session_form($form, &$form_state) {
$form['language_negotiation_session_param'] = array(
'#title' => t('Request/session parameter'),
'#type' => 'textfield',
'#default_value' => config('language.negotiation')
->get('session.parameter'),
'#description' => t('Name of the request/session parameter used to determine the desired language.'),
);
$form_state['redirect'] = 'admin/config/regional/language/detection';
return system_config_form($form, $form_state);
}