/**
 * Implements hook_language_types_info().
 */
function {{ machine_name }}_language_types_info() {
  return [
    'custom_language_type' => [
      'name' => t('Custom language'),
      'description' => t('A custom language type.'),
      'locked' => FALSE,
    ],
    'fixed_custom_language_type' => [
      'locked' => TRUE,
      'fixed' => ['custom_language_negotiation_method'],
    ],
  ];
}