Implements \Drupal\Core\Form\FormInterface::buildForm().
Overrides SystemConfigFormBase::buildForm
public function buildForm(array $form, array &$form_state) {
$config = $this->configFactory
->get('language.negotiation');
$form['language_negotiation_session_param'] = array(
'#title' => t('Request/session parameter'),
'#type' => 'textfield',
'#default_value' => $config
->get('session.parameter'),
'#description' => t('Name of the request/session parameter used to determine the desired language.'),
);
$form_state['redirect'] = 'admin/config/regional/language/detection';
return parent::buildForm($form, $form_state);
}