Index: src/Plugin/Field/FieldWidget/InlineParagraphsWidget.php
IDEA additional info:
Subsystem: com.intellij.openapi.diff.impl.patch.CharsetEP
<+>UTF-8
===================================================================
--- src/Plugin/Field/FieldWidget/InlineParagraphsWidget.php	(revision edf36e039c3b243be03b22d400a7b1cc0aae59eb)
+++ src/Plugin/Field/FieldWidget/InlineParagraphsWidget.php	(revision )
@@ -4,7 +4,6 @@
 
 use Drupal\Component\Utility\NestedArray;
 use Drupal\Component\Utility\Html;
-use Drupal\Core\Entity\Entity;
 use Drupal\Core\Entity\Entity\EntityFormDisplay;
 use Drupal\Core\Entity\EntityInterface;
 use Drupal\Core\Entity\RevisionableInterface;
@@ -14,6 +13,7 @@
 use Drupal\Core\Form\FormStateInterface;
 use Drupal\Core\Field\FieldItemListInterface;
 use Drupal\Core\Render\Element;
+use Drupal\field\Entity\FieldConfig;
 use Drupal\paragraphs;
 use Symfony\Component\Validator\ConstraintViolationInterface;
 
@@ -232,6 +232,26 @@
           }
         }
       }
+
+      /**
+       * Localised Paragraphs.
+       *
+       *  If the parent field is marked as translatable, assume paragraphs
+       *  to be localized (host entity expects different paragraphs for
+       *  different languages)
+       */
+      else if ($items->getFieldDefinition()->isTranslatable()) {
+        $paragraphs_entity = $this->cloneReferencedEntity($paragraphs_entity, $entity_manager, $target_type, $langcode);
+      }
+
+      /**
+       * Translated Paragraphs
+       *
+       *  If the parent field is not translatable, assume the paragraph
+       *  entity itself (rather the fields within it) are marked as
+       *  translatable. (host entity expects same paragraphs in different
+       *  languages).
+       */
       else {
         // Add translation if missing for the target language.
         if (!$paragraphs_entity->hasTranslation($langcode)) {
@@ -332,7 +352,7 @@
           }
 
           // Hide the button when translating.
-          $button_access = $paragraphs_entity->access('delete') && !$this->isTranslating;
+          $button_access = $paragraphs_entity->access('delete') && (!$this->isTranslating || $items->getFieldDefinition()->isTranslatable());
           $links['remove_button'] = array(
             '#type' => 'submit',
             '#value' => $this->t('Remove'),
@@ -733,7 +753,7 @@
     foreach ($bundles as $machine_name => $bundle) {
 
       if ($dragdrop_settings || (!count($this->getSelectionHandlerSetting('target_bundles'))
-        || in_array($machine_name, $this->getSelectionHandlerSetting('target_bundles')))) {
+          || in_array($machine_name, $this->getSelectionHandlerSetting('target_bundles')))) {
         $options[$machine_name] = $bundle['label'];
 
         if ($access_control_handler->createAccess($machine_name)) {
@@ -794,7 +814,7 @@
       $elements['add_more'] = array(
         '#type' => 'container',
         '#theme_wrappers' => array('paragraphs_dropbutton_wrapper'),
-        '#access' => !$this->isTranslating,
+        '#access' => (!$this->isTranslating || $items->getFieldDefinition()->isTranslatable()),
       );
 
       if (count($access_options)) {
@@ -830,7 +850,7 @@
             );
             if ($drop_button) {
               $elements['add_more']['add_more_button_' . $machine_name]['#prefix'] = '<li>';
-              $elements['add_more']['add_more_button_' . $machine_name]['#suffix'] = '</li>';
+              $elements['add_more']['add_more_button_' . $machine_name]['#suffix'] = '<li>';
             }
           }
         }
@@ -1082,9 +1102,8 @@
 
         /** @var \Drupal\Core\Entity\Display\EntityFormDisplayInterface $display */
         $display =  $widget_state['paragraphs'][$item['_original_delta']]['display'];
-        if ($widget_state['paragraphs'][$delta]['mode'] == 'edit') {
-          $display->extractFormValues($paragraphs_entity, $element[$item['_original_delta']]['subform'], $form_state);
+        $display->extractFormValues($paragraphs_entity, $element[$item['_original_delta']]['subform'], $form_state);
-        }
+
         $paragraphs_entity->setNewRevision($new_revision);
         // A content entity form saves without any rebuild. It needs to set the
         // language to update it in case of language change.
@@ -1188,5 +1207,50 @@
       }
     }
     return $element;
+  }
+
+  /**
+   * Clones Paragraphs (and field_collections) recursively, preparing them to be
+   * passed to the translated paragraph widget.
+   *
+   * @param $entity_to_clone
+   * @param $entity_manager
+   * @param $target_type
+   * @param $langcode
+   * @return array
+   */
+  protected function cloneReferencedEntity($entity_to_clone, $entity_manager, $target_type, $langcode) {
+    // Get the paragraph item as an array of values.
+    $paragraph_array = $entity_to_clone->toArray();
+    $entity_type = $entity_manager->getDefinition($target_type);
+    $bundle_key = $entity_type->getKey('bundle');
+
+    // Create a new entity for this language.
+    $new_entity = array(
+      $bundle_key => $entity_to_clone->bundle(),
+      'langcode' => $langcode
+    );
+
+    // Loop through all fields in the paragraph and add to new entity.
+    foreach ($entity_to_clone->getFieldDefinitions() as $key => $field) {
+      // Check that the value is a field config and not empty.
+      if ($field instanceof FieldConfig && !empty($paragraph_array[$key])) {
+        if(in_array($field->getSetting('target_type'), ['field_collection_item', 'paragraph'])){
+          // we need to get the actual field object from the original entity being cloned.
+          $entities = $entity_to_clone->get($key)->referencedEntities();
+          $cloned_entites = [];
+          foreach ($entities as $entity){
+            /** @var EntityInterface $entity */
+            $cloned_entites_target_type = $entity->getEntityTypeId();
+            $cloned_entites[] = $this->cloneReferencedEntity($entity, $entity_manager, $cloned_entites_target_type, $langcode);
+          }
+          $new_entity[$key] = $cloned_entites;
+        }
+        else{
+          $new_entity[$key] = $paragraph_array[$key];
+        }
+      }
+    }
+    return $entity_manager->getStorage($target_type)->create($new_entity);
   }
 }