How to translate contact message field labels

Question

I have multiple contact forms in my multilingual D8 website:

• questions or remarks
• order gift voucher

Those have custom fields (like field_phone, field_amount, ...)

For my custom fields, the form-element-label.html.twig with label is a string, whilst the core "message" field is a TranslatableMarkup object.

How do I provide the translation for field labels of these forms?

Answer 1

Standard fields of a contact form are predefined in code. Custom fields are in configuration and the translation works differently.

This should work:

1. Enable the module "Configuration translation"
2. /admin/structure/contact/manage/feedback/fields
3. Add field
4. Enter an english label
5. Configure the field type
6. Choose Tab "Translate contact message fields"
7. Add a translation in another language
8. Enter a translated label

Answer 2

A possible (temporary) sollution:

In theme_form_contact_message_form_alter I've put an array with all the fields that need translation. Based on those fields I change the "#title" variables if the "#title" variable is a string. A TranslatableMarkup "#title" doesn't need another translation:

function theme_form_contact_message_form_alter(&$form, 

  \Drupal\Core\Form\FormStateInterface $form_state, $form_id) {

  // Change items

  $title_items = array(
    'subject',
    'message',
    'name',
    'mail',
    'field_amount' ,
    'field_phone',
    'field_receiver',
  );

  foreach ($title_items as $form_item) {
    if(isset($form[$form_item])) {
      $item = $form[$form_item];
      if($item['#type'] == 'container') {
        if(isset($form[$form_item]['widget'][0]['value']['#title'])) {
          if(is_string($form[$form_item]['widget'][0]['value']['#title'])) {
            $form[$form_item]['widget'][0]['value']['#title'] = $form[$form_item]['widget']['#title'] = t($form[$form_item]['widget'][0]['value']['#title']);
          }
        }
      } elseif ($form[$form_item]['#type'] != 'item') {
        // Make sure the item is not a pre-filled element.
        if(isset($item['#title']) && is_string($item['#title'])) {
          if(is_string($item['#title'])) {
            $form[$form_item]['#title'] = t($form[$form_item]['#title']);
          }
        }
      }
    }
  }
}