diff --git a/core/lib/Drupal/Core/Entity/EntityFormController.php b/core/lib/Drupal/Core/Entity/EntityFormController.php
index 07dd8f3..147baff 100644
--- a/core/lib/Drupal/Core/Entity/EntityFormController.php
+++ b/core/lib/Drupal/Core/Entity/EntityFormController.php
@@ -305,10 +305,9 @@ public function validate(array $form, array &$form_state) {
     // Map errors back to form elements.
     if ($violations) {
       foreach ($violations as $field_name => $field_violations) {
-        $langcode = field_is_translatable($entity_type , field_info_field($entity_type, $field_name)) ? $entity_langcode : Language::LANGCODE_NOT_SPECIFIED;
-        $field_state = field_form_get_state($form['#parents'], $field_name, $langcode, $form_state);
+        $field_state = field_form_get_state($form['#parents'], $field_name, $form_state);
         $field_state['constraint_violations'] = $field_violations;
-        field_form_set_state($form['#parents'], $field_name, $langcode, $form_state, $field_state);
+        field_form_set_state($form['#parents'], $field_name, $form_state, $field_state);
       }
 
       field_invoke_method('flagErrors', _field_invoke_widget_target($form_state['form_display']), $entity, $form, $form_state);
@@ -339,7 +338,6 @@ public function submit(array $form, array &$form_state) {
     form_state_values_clean($form_state);
 
     $this->updateFormLangcode($form_state);
-    $this->submitEntityLanguage($form, $form_state);
     $this->entity = $this->buildEntity($form, $form_state);
     return $this->entity;
   }
@@ -415,42 +413,6 @@ protected function updateFormLangcode(array &$form_state) {
   }
 
   /**
-   * Handle possible entity language changes.
-   *
-   * @param array $form
-   *   An associative array containing the structure of the form.
-   * @param array $form_state
-   *   A reference to a keyed array containing the current state of the form.
-   */
-  protected function submitEntityLanguage(array $form, array &$form_state) {
-    $entity = $this->entity;
-    $entity_type = $entity->entityType();
-
-    if (field_has_translation_handler($entity_type)) {
-      // If we are editing the default language values, we use the submitted
-      // entity language as the new language for fields to handle any language
-      // change. Otherwise the current form language is the proper value, since
-      // in this case it is not supposed to change.
-      $current_langcode = $this->isDefaultFormLangcode($form_state) ? $form_state['values']['langcode'] : $this->getFormLangcode($form_state);
-
-      foreach (field_info_instances($entity_type, $entity->bundle()) as $instance) {
-        $field = $instance->getField();
-        $field_name = $field->name;
-        if (isset($form[$field_name]['#language'])) {
-          $previous_langcode = $form[$field_name]['#language'];
-
-          // Handle a possible language change: new language values are inserted,
-          // previous ones are deleted.
-          if ($field['translatable'] && $previous_langcode != $current_langcode) {
-            $form_state['values'][$field_name][$current_langcode] = $form_state['values'][$field_name][$previous_langcode];
-            $form_state['values'][$field_name][$previous_langcode] = array();
-          }
-        }
-      }
-    }
-  }
-
-  /**
    * Implements \Drupal\Core\Entity\EntityFormControllerInterface::buildEntity().
    */
   public function buildEntity(array $form, array &$form_state) {
diff --git a/core/lib/Drupal/Core/Entity/EntityFormControllerNG.php b/core/lib/Drupal/Core/Entity/EntityFormControllerNG.php
index f760057..11396d9 100644
--- a/core/lib/Drupal/Core/Entity/EntityFormControllerNG.php
+++ b/core/lib/Drupal/Core/Entity/EntityFormControllerNG.php
@@ -38,16 +38,6 @@ public function form(array $form, array &$form_state) {
   }
 
   /**
-   * Overrides EntityFormController::submitEntityLanguage().
-   */
-  protected function submitEntityLanguage(array $form, array &$form_state) {
-    // Nothing to do here, as original field values are always stored with
-    // Language::LANGCODE_DEFAULT language.
-    // @todo Delete this method when merging EntityFormControllerNG with
-    //   EntityFormController.
-  }
-
-  /**
    * Overrides EntityFormController::buildEntity().
    */
   public function buildEntity(array $form, array &$form_state) {
diff --git a/core/modules/edit/lib/Drupal/edit/Form/EditFieldForm.php b/core/modules/edit/lib/Drupal/edit/Form/EditFieldForm.php
index 6faa0c9..1477e46 100644
--- a/core/modules/edit/lib/Drupal/edit/Form/EditFieldForm.php
+++ b/core/modules/edit/lib/Drupal/edit/Form/EditFieldForm.php
@@ -133,9 +133,7 @@ protected function buildEntity(array $form, array &$form_state) {
    */
   protected function simplify(array &$form, array &$form_state) {
     $field_name = $form_state['field_name'];
-    $langcode = $form_state['langcode'];
-
-    $widget_element =& $form[$field_name][$langcode];
+    $widget_element =& $form[$field_name]['widget'];
 
     // Hide the field label from displaying within the form, because JavaScript
     // displays the equivalent label that was provided within an HTML data
diff --git a/core/modules/field/field.deprecated.inc b/core/modules/field/field.deprecated.inc
index 25677ac..8ac601e 100644
--- a/core/modules/field/field.deprecated.inc
+++ b/core/modules/field/field.deprecated.inc
@@ -483,15 +483,10 @@ function field_read_instances($conditions = array(), $include_additional = array
  *   // most common case), and will therefore be repeated as many times as
  *   // needed, or 'multiple-values' (one single widget allows the input of
  *   // several values, e.g checkboxes, select box...).
- *   // The sub-array is nested into a $langcode key where $langcode has the
- *   // same value of the $langcode parameter above.
- *   // The '#language' key holds the same value of $langcode and it is used
- *   // to access the field sub-array when $langcode is unknown.
  *   'field_foo' => array(
- *     '#tree' => TRUE,
- *     '#field_name' => The name of the field,
- *     '#language' => $langcode,
- *     $langcode => array(
+ *     '#access' => TRUE if the current user has 'edit' grants for the field,
+ *       FALSE if not.
+ *     'widget' => array(
  *       '#field_name' => The name of the field,
  *       '#language' => $langcode,
  *       '#field_parents' => The 'parents' space for the field in the form,
@@ -634,10 +629,9 @@ function field_attach_form_validate(EntityInterface $entity, $form, &$form_state
         $has_violations = TRUE;
 
         // Place violations in $form_state.
-        $langcode = field_is_translatable($entity->entityType(), field_info_field($entity->entityType(), $field_name)) ? $entity->language()->id : Language::LANGCODE_NOT_SPECIFIED;
-        $field_state = field_form_get_state($form['#parents'], $field_name, $langcode, $form_state);
+        $field_state = field_form_get_state($form['#parents'], $field_name, $form_state);
         $field_state['constraint_violations'] = $field_violations;
-        field_form_set_state($form['#parents'], $field_name, $langcode, $form_state, $field_state);
+        field_form_set_state($form['#parents'], $field_name, $form_state, $field_state);
       }
     }
   }
diff --git a/core/modules/field/field.form.inc b/core/modules/field/field.form.inc
index d71c4fd..1ba3e9c 100644
--- a/core/modules/field/field.form.inc
+++ b/core/modules/field/field.form.inc
@@ -125,11 +125,10 @@ function _field_sort_items_value_helper($a, $b) {
 function field_form_element_after_build($element, &$form_state) {
   $parents = $element['#field_parents'];
   $field_name = $element['#field_name'];
-  $langcode = $element['#language'];
 
-  $field_state = field_form_get_state($parents, $field_name, $langcode, $form_state);
+  $field_state = field_form_get_state($parents, $field_name, $form_state);
   $field_state['array_parents'] = $element['#array_parents'];
-  field_form_set_state($parents, $field_name, $langcode, $form_state, $field_state);
+  field_form_set_state($parents, $field_name, $form_state, $field_state);
 
   return $element;
 }
@@ -149,13 +148,12 @@ function field_add_more_submit($form, &$form_state) {
   // Go one level up in the form, to the widgets container.
   $element = NestedArray::getValue($form, array_slice($button['#array_parents'], 0, -1));
   $field_name = $element['#field_name'];
-  $langcode = $element['#language'];
   $parents = $element['#field_parents'];
 
   // Increment the items count.
-  $field_state = field_form_get_state($parents, $field_name, $langcode, $form_state);
+  $field_state = field_form_get_state($parents, $field_name, $form_state);
   $field_state['items_count']++;
-  field_form_set_state($parents, $field_name, $langcode, $form_state, $field_state);
+  field_form_set_state($parents, $field_name, $form_state, $field_state);
 
   $form_state['rebuild'] = TRUE;
 }
@@ -194,8 +192,6 @@ function field_add_more_js($form, $form_state) {
  *   The array of #parents where the field lives in the form.
  * @param $field_name
  *   The field name.
- * @param $langcode
- *   The language in which the field values are entered.
  * @param $form_state
  *   The form state.
  *
@@ -209,8 +205,8 @@ function field_add_more_js($form, $form_state) {
  *
  * @see field_form_set_state()
  */
-function field_form_get_state($parents, $field_name, $langcode, &$form_state) {
-  $form_state_parents = _field_form_state_parents($parents, $field_name, $langcode);
+function field_form_get_state($parents, $field_name, &$form_state) {
+  $form_state_parents = _field_form_state_parents($parents, $field_name);
   return NestedArray::getValue($form_state, $form_state_parents);
 }
 
@@ -221,8 +217,6 @@ function field_form_get_state($parents, $field_name, $langcode, &$form_state) {
  *   The array of #parents where the field lives in the form.
  * @param $field_name
  *   The field name.
- * @param $langcode
- *   The language in which the field values are entered.
  * @param $form_state
  *   The form state.
  * @param $field_state
@@ -231,8 +225,8 @@ function field_form_get_state($parents, $field_name, $langcode, &$form_state) {
  *
  * @see field_form_get_state()
  */
-function field_form_set_state($parents, $field_name, $langcode, &$form_state, $field_state) {
-  $form_state_parents = _field_form_state_parents($parents, $field_name, $langcode);
+function field_form_set_state($parents, $field_name, &$form_state, $field_state) {
+  $form_state_parents = _field_form_state_parents($parents, $field_name);
   NestedArray::setValue($form_state, $form_state_parents, $field_state);
 }
 
@@ -243,30 +237,14 @@ function field_form_set_state($parents, $field_name, $langcode, &$form_state, $f
  *   The array of #parents where the field lives in the form.
  * @param $field_name
  *   The field name.
- * @param $langcode
- *   The language in which the field values are entered.
  *
  * @return
  *   The location of processing information within $form_state.
  */
-function _field_form_state_parents($parents, $field_name, $langcode) {
-  // To ensure backwards compatibility on regular entity forms for widgets that
-  // still access $form_state['field'][$field_name] directly,
-  // - top-level fields (empty $parents) are placed directly under
-  //   $form_state['fields'][$field_name].
-  // - Other fields are placed under
-  //   $form_state['field']['#parents'][...$parents...]['#fields'][$field_name]
-  //   to avoid clashes between field names and $parents parts.
-  // @todo Remove backwards compatibility in Drupal 8, and use a unique
-  // $form_state['field'][...$parents...]['#fields'][$field_name] structure.
-  if (!empty($parents)) {
-    $form_state_parents = array_merge(array('#parents'), $parents, array('#fields'));
-  }
-  else {
-    $form_state_parents = array();
-  }
-  $form_state_parents = array_merge(array('field'), $form_state_parents, array($field_name, $langcode));
-
-  return $form_state_parents;
+function _field_form_state_parents($parents, $field_name) {
+  // Field processing data is placed at
+  // $form_state['field']['#parents'][...$parents...]['#fields'][$field_name],
+  // to avoid clashes between field names and $parents parts.
+  return array_merge(array('field', '#parents'), $parents, array('#fields', $field_name));
 }
 
diff --git a/core/modules/field/lib/Drupal/field/Plugin/Type/FieldType/ConfigField.php b/core/modules/field/lib/Drupal/field/Plugin/Type/FieldType/ConfigField.php
index eb2e4db..4002dd5 100644
--- a/core/modules/field/lib/Drupal/field/Plugin/Type/FieldType/ConfigField.php
+++ b/core/modules/field/lib/Drupal/field/Plugin/Type/FieldType/ConfigField.php
@@ -103,9 +103,9 @@ public function defaultValuesFormValidate(array $element, array &$form, array &$
     if (count($violations)) {
       // Store reported errors in $form_state.
       $field_name = $this->getFieldDefinition()->getFieldName();
-      $field_state = field_form_get_state($element['#parents'], $field_name, $langcode, $form_state);
+      $field_state = field_form_get_state($element['#parents'], $field_name, $form_state);
       $field_state['constraint_violations'] = $violations;
-      field_form_set_state($element['#parents'], $field_name, $langcode, $form_state, $field_state);
+      field_form_set_state($element['#parents'], $field_name, $form_state, $field_state);
 
       // Assign reported errors to the correct form element.
       $widget->flagErrors($entity, $langcode, $this, $element, $form_state);
diff --git a/core/modules/field/lib/Drupal/field/Plugin/Type/Widget/WidgetBase.php b/core/modules/field/lib/Drupal/field/Plugin/Type/Widget/WidgetBase.php
index 4cf4556..e6839d3 100644
--- a/core/modules/field/lib/Drupal/field/Plugin/Type/Widget/WidgetBase.php
+++ b/core/modules/field/lib/Drupal/field/Plugin/Type/Widget/WidgetBase.php
@@ -58,21 +58,16 @@ public function __construct($plugin_id, array $plugin_definition, FieldDefinitio
    */
   public function form(EntityInterface $entity, $langcode, FieldInterface $items, array &$form, array &$form_state, $get_delta = NULL) {
     $field_name = $this->fieldDefinition->getFieldName();
-
     $parents = $form['#parents'];
 
-    $addition = array(
-      $field_name => array(),
-    );
-
     // Store field information in $form_state.
-    if (!field_form_get_state($parents, $field_name, $langcode, $form_state)) {
+    if (!field_form_get_state($parents, $field_name, $form_state)) {
       $field_state = array(
         'items_count' => count($items),
         'array_parents' => array(),
         'constraint_violations' => array(),
       );
-      field_form_set_state($parents, $field_name, $langcode, $form_state, $field_state);
+      field_form_set_state($parents, $field_name, $form_state, $field_state);
     }
 
     // Collect widget elements.
@@ -110,37 +105,38 @@ public function form(EntityInterface $entity, $langcode, FieldInterface $items,
       $elements = $this->formMultipleElements($entity, $items, $langcode, $form, $form_state);
     }
 
-    // Also aid in theming of field widgets by rendering a classified
-    // container.
-    $addition[$field_name] = array(
-      '#type' => 'container',
-      '#attributes' => array(
-        'class' => array(
-          'field-type-' . drupal_html_class($this->fieldDefinition->getFieldType()),
-          'field-name-' . drupal_html_class($field_name),
-          'field-widget-' . drupal_html_class($this->getPluginId()),
-        ),
-      ),
-    );
-
     // Populate the 'array_parents' information in $form_state['field'] after
     // the form is built, so that we catch changes in the form structure performed
     // in alter() hooks.
     $elements['#after_build'][] = 'field_form_element_after_build';
     $elements['#field_name'] = $field_name;
+    // @todo Not strictly needed anymore.
     $elements['#language'] = $langcode;
     $elements['#field_parents'] = $parents;
-
-    $addition[$field_name] += array(
-      '#tree' => TRUE,
-      // The '#language' key can be used to access the field's form element
-      // when $langcode is unknown.
-      '#language' => $langcode,
-      $langcode => $elements,
-      '#access' => $this->checkFieldAccess('edit', $entity),
+    // Enforce the structure of submitted values.
+    $elements['#parents'] = array_merge($parents, array($field_name));
+    // Most widgets need their internal structure preserved in submitted values.
+    $elements += array('#tree' => TRUE);
+
+    $return = array(
+      $field_name => array(
+        // Aid in theming of widgets by rendering a classified container.
+        '#type' => 'container',
+        // Assign a different parent, to keep the main id for the widget itself.
+        '#parents' => array_merge($parents, array($field_name . '_wrapper')),
+        '#attributes' => array(
+          'class' => array(
+            'field-type-' . drupal_html_class($this->fieldDefinition->getFieldType()),
+            'field-name-' . drupal_html_class($field_name),
+            'field-widget-' . drupal_html_class($this->getPluginId()),
+          ),
+        ),
+        '#access' => $this->checkFieldAccess('edit', $entity),
+        'widget' => $elements,
+      ),
     );
 
-    return $addition;
+    return $return;
   }
 
   /**
@@ -159,7 +155,7 @@ protected function formMultipleElements(EntityInterface $entity, FieldInterface
     // Determine the number of widgets to display.
     switch ($cardinality) {
       case FIELD_CARDINALITY_UNLIMITED:
-        $field_state = field_form_get_state($parents, $field_name, $langcode, $form_state);
+        $field_state = field_form_get_state($parents, $field_name, $form_state);
         $max = $field_state['items_count'];
         $is_multiple = TRUE;
         break;
@@ -285,7 +281,7 @@ public function extractFormValues(EntityInterface $entity, $langcode, FieldInter
     $field_name = $this->fieldDefinition->getFieldName();
 
     // Extract the values from $form_state['values'].
-    $path = array_merge($form['#parents'], array($field_name, $langcode));
+    $path = array_merge($form['#parents'], array($field_name));
     $key_exists = NULL;
     $values = NestedArray::getValue($form_state['values'], $path, $key_exists);
 
@@ -322,12 +318,12 @@ public function extractFormValues(EntityInterface $entity, $langcode, FieldInter
       $items->filterEmptyValues();
 
       // Put delta mapping in $form_state, so that flagErrors() can use it.
-      $field_state = field_form_get_state($form['#parents'], $field_name, $langcode, $form_state);
+      $field_state = field_form_get_state($form['#parents'], $field_name, $form_state);
       foreach ($items as $delta => $item) {
         $field_state['original_deltas'][$delta] = $item->_original_delta;
         unset($item->_original_delta);
       }
-      field_form_set_state($form['#parents'], $field_name, $langcode, $form_state, $field_state);
+      field_form_set_state($form['#parents'], $field_name, $form_state, $field_state);
     }
   }
 
@@ -337,7 +333,7 @@ public function extractFormValues(EntityInterface $entity, $langcode, FieldInter
   public function flagErrors(EntityInterface $entity, $langcode, FieldInterface $items, array $form, array &$form_state) {
     $field_name = $this->fieldDefinition->getFieldName();
 
-    $field_state = field_form_get_state($form['#parents'], $field_name, $langcode, $form_state);
+    $field_state = field_form_get_state($form['#parents'], $field_name, $form_state);
 
     if (!empty($field_state['constraint_violations'])) {
       // Locate the correct element in the the form.
@@ -377,7 +373,7 @@ public function flagErrors(EntityInterface $entity, $langcode, FieldInterface $i
         }
         // Reinitialize the errors list for the next submit.
         $field_state['constraint_violations'] = array();
-        field_form_set_state($form['#parents'], $field_name, $langcode, $form_state, $field_state);
+        field_form_set_state($form['#parents'], $field_name, $form_state, $field_state);
       }
     }
   }
diff --git a/core/modules/file/file.field.inc b/core/modules/file/file.field.inc
index a40a44b..09d031d 100644
--- a/core/modules/file/file.field.inc
+++ b/core/modules/file/file.field.inc
@@ -548,7 +548,6 @@ function file_field_widget_submit($form, &$form_state) {
   // Go one level up in the form, to the widgets container.
   $element = NestedArray::getValue($form, array_slice($button['#array_parents'], 0, -1));
   $field_name = $element['#field_name'];
-  $langcode = $element['#language'];
   $parents = $element['#field_parents'];
 
   $submitted_values = NestedArray::getValue($form_state['values'], array_slice($button['#parents'], 0, -2));
@@ -581,9 +580,9 @@ function file_field_widget_submit($form, &$form_state) {
   NestedArray::setValue($form_state['values'], array_slice($button['#parents'], 0, -2), $submitted_values);
 
   // Update items.
-  $field_state = field_form_get_state($parents, $field_name, $langcode, $form_state);
+  $field_state = field_form_get_state($parents, $field_name, $form_state);
   $field_state['items'] = $submitted_values;
-  field_form_set_state($parents, $field_name, $langcode, $form_state, $field_state);
+  field_form_set_state($parents, $field_name, $form_state, $field_state);
 }
 
 /**
diff --git a/core/modules/file/lib/Drupal/file/Plugin/field/widget/FileWidget.php b/core/modules/file/lib/Drupal/file/Plugin/field/widget/FileWidget.php
index 1e12c5b..a086d2c 100644
--- a/core/modules/file/lib/Drupal/file/Plugin/field/widget/FileWidget.php
+++ b/core/modules/file/lib/Drupal/file/Plugin/field/widget/FileWidget.php
@@ -70,7 +70,7 @@ protected function formMultipleElements(EntityInterface $entity, FieldInterface
     // Load the items for form rebuilds from the field state as they might not be
     // in $form_state['values'] because of validation limitations. Also, they are
     // only passed in as $items when editing existing entities.
-    $field_state = field_form_get_state($parents, $field_name, $langcode, $form_state);
+    $field_state = field_form_get_state($parents, $field_name, $form_state);
     if (isset($field_state['items'])) {
       $items->setValue($field_state['items']);
     }
diff --git a/core/modules/forum/forum.module b/core/modules/forum/forum.module
index 0f076c4..1d1e06e 100644
--- a/core/modules/forum/forum.module
+++ b/core/modules/forum/forum.module
@@ -263,7 +263,6 @@ function forum_uri($forum) {
  */
 function forum_node_validate(EntityInterface $node, $form) {
   if (Drupal::service('forum_manager')->checkNodeType($node)) {
-    $langcode = $form['taxonomy_forums']['#language'];
     // vocabulary is selected, not a "container" term.
     if (!$node->taxonomy_forums->isEmpty()) {
       // Extract the node's proper topic ID.
@@ -565,16 +564,16 @@ function forum_form_node_form_alter(&$form, &$form_state, $form_id) {
   }
 
   if (isset($form['taxonomy_forums'])) {
-    $langcode = $form['taxonomy_forums']['#language'];
+    $widget =& $form['taxonomy_forums']['widget'];
     // Make the vocabulary required for 'real' forum-nodes.
-    $form['taxonomy_forums'][$langcode]['#required'] = TRUE;
-    $form['taxonomy_forums'][$langcode]['#multiple'] = FALSE;
-    if (empty($form['taxonomy_forums'][$langcode]['#default_value'])) {
+    $widget['#required'] = TRUE;
+    $widget['#multiple'] = FALSE;
+    if (empty($widget['#default_value'])) {
       // If there is no default forum already selected, try to get the forum
       // ID from the URL (e.g., if we are on a page like node/add/forum/2, we
       // expect "2" to be the ID of the forum that was requested).
       $requested_forum_id = arg(3);
-      $form['taxonomy_forums'][$langcode]['#default_value'] = is_numeric($requested_forum_id) ? $requested_forum_id : '';
+      $widget['#default_value'] = is_numeric($requested_forum_id) ? $requested_forum_id : '';
     }
   }
 }