/**
 * Implements hook_ENTITY_TYPE_translation_delete().
 */
function {{ machine_name }}_ENTITY_TYPE_translation_delete(\Drupal\Core\Entity\EntityInterface $translation) {
  $variables = [
    '@language' => $translation->language()->getName(),
    '@label' => $translation->label(),
  ];
  \Drupal::logger('example')->notice('The @language translation of @label has just been deleted.', $variables);
}