diff --git a/core/lib/Drupal/Core/Entity/Annotation/FieldType.php b/core/lib/Drupal/Core/Entity/Annotation/FieldType.php
index 3ced435..e73ae01 100644
--- a/core/lib/Drupal/Core/Entity/Annotation/FieldType.php
+++ b/core/lib/Drupal/Core/Entity/Annotation/FieldType.php
@@ -8,6 +8,7 @@
 namespace Drupal\Core\Entity\Annotation;
 
 use Drupal\Component\Annotation\Plugin;
+use Drupal\Core\TypedData\Annotation\DataType;
 
 /**
  * Defines a FieldType annotation object.
@@ -17,7 +18,7 @@
  *
  * @Annotation
  */
-class FieldType extends Plugin {
+class FieldType extends DataType {
 
   /**
    * The plugin ID.
@@ -110,10 +111,16 @@ class FieldType extends Plugin {
   /**
    * A boolean stating that fields of this type cannot be created through the UI.
    *
-   * If TRUE, fields of this type can only be created programmatically.
+   * If TRUE or the field type is not configurable, fields of this type can only
+   * be created programmatically.
    *
    * @var boolean
    */
   public $no_ui = FALSE;
 
+  /**
+   * {@inheritdoc}
+   */
+  public $list_class = '\Drupal\field\Plugin\Type\FieldType\ConfigField';
+
 }
diff --git a/core/lib/Drupal/Core/Entity/Field/FieldTypePluginManager.php b/core/lib/Drupal/Core/Entity/Field/FieldTypePluginManager.php
index 9f9ceb8..f16ec74 100644
--- a/core/lib/Drupal/Core/Entity/Field/FieldTypePluginManager.php
+++ b/core/lib/Drupal/Core/Entity/Field/FieldTypePluginManager.php
@@ -25,7 +25,6 @@ class FieldTypePluginManager extends DefaultPluginManager {
   protected $defaults = array(
     'settings' => array(),
     'instance_settings' => array(),
-    'list_class' => '\Drupal\field\Plugin\Type\FieldType\ConfigField',
   );
 
   /**
diff --git a/core/lib/Drupal/Core/Entity/Plugin/DataType/LanguageItem.php b/core/lib/Drupal/Core/Entity/Plugin/DataType/LanguageItem.php
deleted file mode 100644
index 68526f5..0000000
--- a/core/lib/Drupal/Core/Entity/Plugin/DataType/LanguageItem.php
+++ /dev/null
@@ -1,109 +0,0 @@
-<?php
-
-/**
- * @file
- * Contains \Drupal\Core\Entity\Plugin\DataType\LanguageItem.
- */
-
-namespace Drupal\Core\Entity\Plugin\DataType;
-
-use Drupal\Core\TypedData\Annotation\DataType;
-use Drupal\Core\Annotation\Translation;
-use Drupal\Core\Entity\Field\FieldItemBase;
-use Drupal\Core\Language\Language;
-
-/**
- * Defines the 'language_field' entity field item.
- *
- * @DataType(
- *   id = "language_field",
- *   label = @Translation("Language field item"),
- *   description = @Translation("An entity field referencing a language."),
- *   list_class = "\Drupal\Core\Entity\Field\Field",
- *   constraints = {
- *     "ComplexData" = {
- *       "value" = {"Length" = {"max" = 12}}
- *     }
- *   }
- * )
- */
-class LanguageItem extends FieldItemBase {
-
-  /**
-   * Definitions of the contained properties.
-   *
-   * @see LanguageItem::getPropertyDefinitions()
-   *
-   * @var array
-   */
-  static $propertyDefinitions;
-
-  /**
-   * Implements \Drupal\Core\TypedData\ComplexDataInterface::getPropertyDefinitions().
-   */
-  public function getPropertyDefinitions() {
-    if (!isset(static::$propertyDefinitions)) {
-      static::$propertyDefinitions['value'] = array(
-        'type' => 'string',
-        'label' => t('Language code'),
-      );
-      static::$propertyDefinitions['language'] = array(
-        'type' => 'language_reference',
-        'label' => t('Language object'),
-        'description' => t('The referenced language'),
-        // The language object is retrieved via the language code.
-        'computed' => TRUE,
-        'read-only' => FALSE,
-      );
-    }
-    return static::$propertyDefinitions;
-  }
-
-  /**
-   * Overrides \Drupal\Core\Entity\Field\FieldItemBase::get().
-   */
-  public function setValue($values, $notify = TRUE) {
-    // Treat the values as property value of the language property, if no array
-    // is given as this handles language codes and objects.
-    if (isset($values) && !is_array($values)) {
-      // Directly update the property instead of invoking the parent, so that
-      // the language property can take care of updating the language code
-      // property.
-      $this->properties['language']->setValue($values, $notify);
-      // If notify was FALSE, ensure the value property gets synched.
-      if (!$notify) {
-        $this->set('value', $this->properties['language']->getTargetIdentifier(), FALSE);
-      }
-    }
-    else {
-      // Make sure that the 'language' property gets set as 'value'.
-      if (isset($values['value']) && !isset($values['language'])) {
-        $values['language'] = $values['value'];
-      }
-      parent::setValue($values, $notify);
-    }
-  }
-
-  /**
-   * {@inheritdoc}
-   */
-  public function applyDefaultValue($notify = TRUE) {
-    // Default to LANGCODE_NOT_SPECIFIED.
-    $this->setValue(array('value' => Language::LANGCODE_NOT_SPECIFIED), $notify);
-    return $this;
-  }
-
-  /**
-   * {@inheritdoc}
-   */
-  public function onChange($property_name) {
-    // Make sure that the value and the language property stay in sync.
-    if ($property_name == 'value') {
-      $this->properties['language']->setValue($this->value, FALSE);
-    }
-    elseif ($property_name == 'language') {
-      $this->set('value', $this->properties['language']->getTargetIdentifier(), FALSE);
-    }
-    parent::onChange($property_name);
-  }
-}
diff --git a/core/lib/Drupal/Core/Entity/Plugin/field/field_type/LanguageItem.php b/core/lib/Drupal/Core/Entity/Plugin/field/field_type/LanguageItem.php
new file mode 100644
index 0000000..4b7ffbe
--- /dev/null
+++ b/core/lib/Drupal/Core/Entity/Plugin/field/field_type/LanguageItem.php
@@ -0,0 +1,111 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\Core\Entity\Plugin\field\field_type\LanguageItem.
+ */
+
+namespace Drupal\Core\Entity\Plugin\field\field_type;
+
+use Drupal\Core\Entity\Annotation\FieldType;
+use Drupal\Core\Annotation\Translation;
+use Drupal\Core\Entity\Field\FieldItemBase;
+use Drupal\Core\Language\Language;
+
+/**
+ * Defines the 'field_item:language' entity field item.
+ *
+ * @FieldType(
+ *   id = "language",
+ *   module = "system",
+ *   label = @Translation("Language"),
+ *   description = @Translation("An entity field referencing a language."),
+ *   configurable = false,
+ *   list_class = "\Drupal\Core\Entity\Field\Field",
+ *   constraints = {
+ *     "ComplexData" = {
+ *       "value" = {"Length" = {"max" = 12}}
+ *     }
+ *   }
+ * )
+ */
+class LanguageItem extends FieldItemBase {
+
+  /**
+   * Definitions of the contained properties.
+   *
+   * @see LanguageItem::getPropertyDefinitions()
+   *
+   * @var array
+   */
+  static $propertyDefinitions;
+
+  /**
+   * Implements \Drupal\Core\TypedData\ComplexDataInterface::getPropertyDefinitions().
+   */
+  public function getPropertyDefinitions() {
+    if (!isset(static::$propertyDefinitions)) {
+      static::$propertyDefinitions['value'] = array(
+        'type' => 'string',
+        'label' => t('Language code'),
+      );
+      static::$propertyDefinitions['language'] = array(
+        'type' => 'language_reference',
+        'label' => t('Language object'),
+        'description' => t('The referenced language'),
+        // The language object is retrieved via the language code.
+        'computed' => TRUE,
+        'read-only' => FALSE,
+      );
+    }
+    return static::$propertyDefinitions;
+  }
+
+  /**
+   * Overrides \Drupal\Core\Entity\Field\FieldItemBase::get().
+   */
+  public function setValue($values, $notify = TRUE) {
+    // Treat the values as property value of the language property, if no array
+    // is given as this handles language codes and objects.
+    if (isset($values) && !is_array($values)) {
+      // Directly update the property instead of invoking the parent, so that
+      // the language property can take care of updating the language code
+      // property.
+      $this->properties['language']->setValue($values, $notify);
+      // If notify was FALSE, ensure the value property gets synched.
+      if (!$notify) {
+        $this->set('value', $this->properties['language']->getTargetIdentifier(), FALSE);
+      }
+    }
+    else {
+      // Make sure that the 'language' property gets set as 'value'.
+      if (isset($values['value']) && !isset($values['language'])) {
+        $values['language'] = $values['value'];
+      }
+      parent::setValue($values, $notify);
+    }
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function applyDefaultValue($notify = TRUE) {
+    // Default to LANGCODE_NOT_SPECIFIED.
+    $this->setValue(array('value' => Language::LANGCODE_NOT_SPECIFIED), $notify);
+    return $this;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function onChange($property_name) {
+    // Make sure that the value and the language property stay in sync.
+    if ($property_name == 'value') {
+      $this->properties['language']->setValue($this->value, FALSE);
+    }
+    elseif ($property_name == 'language') {
+      $this->set('value', $this->properties['language']->getTargetIdentifier(), FALSE);
+    }
+    parent::onChange($property_name);
+  }
+}
diff --git a/core/modules/aggregator/lib/Drupal/aggregator/FeedStorageController.php b/core/modules/aggregator/lib/Drupal/aggregator/FeedStorageController.php
index 36d87eb..5941afe 100644
--- a/core/modules/aggregator/lib/Drupal/aggregator/FeedStorageController.php
+++ b/core/modules/aggregator/lib/Drupal/aggregator/FeedStorageController.php
@@ -45,7 +45,7 @@ public function baseFieldDefinitions() {
     $fields['langcode'] = array(
       'label' => t('Language code'),
       'description' => t('The feed language code.'),
-      'type' => 'language_field',
+      'type' => 'field_item:language',
     );
     $fields['url'] = array(
       'label' => t('URL'),
diff --git a/core/modules/aggregator/lib/Drupal/aggregator/ItemStorageController.php b/core/modules/aggregator/lib/Drupal/aggregator/ItemStorageController.php
index 016e8ae..bad917e 100644
--- a/core/modules/aggregator/lib/Drupal/aggregator/ItemStorageController.php
+++ b/core/modules/aggregator/lib/Drupal/aggregator/ItemStorageController.php
@@ -50,7 +50,7 @@ public function baseFieldDefinitions() {
     $fields['langcode'] = array(
       'label' => t('Language code'),
       'description' => t('The feed item language code.'),
-      'type' => 'language_field',
+      'type' => 'field_item:language',
     );
     $fields['link'] = array(
       'label' => t('Link'),
diff --git a/core/modules/block/custom_block/lib/Drupal/custom_block/CustomBlockStorageController.php b/core/modules/block/custom_block/lib/Drupal/custom_block/CustomBlockStorageController.php
index 0698234..582b2c6 100644
--- a/core/modules/block/custom_block/lib/Drupal/custom_block/CustomBlockStorageController.php
+++ b/core/modules/block/custom_block/lib/Drupal/custom_block/CustomBlockStorageController.php
@@ -59,7 +59,7 @@ public function baseFieldDefinitions() {
     $properties['langcode'] = array(
       'label' => t('Language code'),
       'description' => t('The comment language code.'),
-      'type' => 'language_field',
+      'type' => 'field_item:language',
     );
     $properties['info'] = array(
       'label' => t('Subject'),
diff --git a/core/modules/comment/lib/Drupal/comment/CommentStorageController.php b/core/modules/comment/lib/Drupal/comment/CommentStorageController.php
index 8cd1a53..ed9f2ea 100644
--- a/core/modules/comment/lib/Drupal/comment/CommentStorageController.php
+++ b/core/modules/comment/lib/Drupal/comment/CommentStorageController.php
@@ -131,7 +131,7 @@ public function baseFieldDefinitions() {
     $properties['langcode'] = array(
       'label' => t('Language code'),
       'description' => t('The comment language code.'),
-      'type' => 'language_field',
+      'type' => 'field_item:language',
     );
     $properties['subject'] = array(
       'label' => t('Subject'),
diff --git a/core/modules/field/field.info.inc b/core/modules/field/field.info.inc
index 7018f94..ad7630f 100644
--- a/core/modules/field/field.info.inc
+++ b/core/modules/field/field.info.inc
@@ -180,7 +180,7 @@ function field_info_field_types($field_type = NULL) {
   }
   else {
     return array_filter(Drupal::service('plugin.manager.entity.field.field_type')->getDefinitions(), function ($definition) {
-      return $definition->configurable;
+      return $definition['configurable'];
     });
   }
 }
diff --git a/core/modules/field/lib/Drupal/field/Plugin/Type/FieldType/LegacyFieldTypeDiscoveryDecorator.php b/core/modules/field/lib/Drupal/field/Plugin/Type/FieldType/LegacyFieldTypeDiscoveryDecorator.php
index 9aa6ab7..e1c226f 100644
--- a/core/modules/field/lib/Drupal/field/Plugin/Type/FieldType/LegacyFieldTypeDiscoveryDecorator.php
+++ b/core/modules/field/lib/Drupal/field/Plugin/Type/FieldType/LegacyFieldTypeDiscoveryDecorator.php
@@ -64,6 +64,7 @@ public function getDefinitions() {
         foreach ($function() as $plugin_id => $definition) {
           $definition['id'] = $plugin_id;
           $definition['module'] = $module;
+          $definition['configurable'] = TRUE;
           $definition['list_class'] = '\Drupal\field\Plugin\field\field_type\LegacyConfigField';
           $definitions[$plugin_id] = $definition;
         }
diff --git a/core/modules/file/lib/Drupal/file/FileStorageController.php b/core/modules/file/lib/Drupal/file/FileStorageController.php
index 10ba8d3..1b4836b 100644
--- a/core/modules/file/lib/Drupal/file/FileStorageController.php
+++ b/core/modules/file/lib/Drupal/file/FileStorageController.php
@@ -58,7 +58,7 @@ public function baseFieldDefinitions() {
     $properties['langcode'] = array(
       'label' => t('Language code'),
       'description' => t('The file language code.'),
-      'type' => 'language_field',
+      'type' => 'field_item:language',
     );
     $properties['uid'] = array(
       'label' => t('User ID'),
diff --git a/core/modules/node/lib/Drupal/node/NodeStorageController.php b/core/modules/node/lib/Drupal/node/NodeStorageController.php
index c3ccc3c..7da6a17 100644
--- a/core/modules/node/lib/Drupal/node/NodeStorageController.php
+++ b/core/modules/node/lib/Drupal/node/NodeStorageController.php
@@ -149,7 +149,7 @@ public function baseFieldDefinitions() {
     $properties['langcode'] = array(
       'label' => t('Language code'),
       'description' => t('The node language code.'),
-      'type' => 'language_field',
+      'type' => 'field_item:language',
     );
     $properties['title'] = array(
       'label' => t('Title'),
diff --git a/core/modules/system/tests/modules/entity_test/lib/Drupal/entity_test/EntityTestStorageController.php b/core/modules/system/tests/modules/entity_test/lib/Drupal/entity_test/EntityTestStorageController.php
index be93b68..a6de832 100644
--- a/core/modules/system/tests/modules/entity_test/lib/Drupal/entity_test/EntityTestStorageController.php
+++ b/core/modules/system/tests/modules/entity_test/lib/Drupal/entity_test/EntityTestStorageController.php
@@ -45,7 +45,7 @@ public function baseFieldDefinitions() {
     $fields['langcode'] = array(
       'label' => t('Language code'),
       'description' => t('The language code of the test entity.'),
-      'type' => 'language_field',
+      'type' => 'field_item:language',
     );
     $fields['name'] = array(
       'label' => t('Name'),
diff --git a/core/modules/taxonomy/lib/Drupal/taxonomy/TermStorageController.php b/core/modules/taxonomy/lib/Drupal/taxonomy/TermStorageController.php
index cb0821c..7c6103c 100644
--- a/core/modules/taxonomy/lib/Drupal/taxonomy/TermStorageController.php
+++ b/core/modules/taxonomy/lib/Drupal/taxonomy/TermStorageController.php
@@ -81,7 +81,7 @@ public function baseFieldDefinitions() {
     $properties['langcode'] = array(
       'label' => t('Language code'),
       'description' => t('The term language code.'),
-      'type' => 'language_field',
+      'type' => 'field_item:language',
     );
     $properties['name'] = array(
       'label' => t('Name'),
diff --git a/core/modules/user/lib/Drupal/user/UserStorageController.php b/core/modules/user/lib/Drupal/user/UserStorageController.php
index 05961e1..e007277 100644
--- a/core/modules/user/lib/Drupal/user/UserStorageController.php
+++ b/core/modules/user/lib/Drupal/user/UserStorageController.php
@@ -190,17 +190,17 @@ public function baseFieldDefinitions() {
     $properties['langcode'] = array(
       'label' => t('Language code'),
       'description' => t('The user language code.'),
-      'type' => 'language_field',
+      'type' => 'field_item:language',
     );
     $properties['preferred_langcode'] = array(
       'label' => t('Language code'),
       'description' => t("The user's preferred langcode for receiving emails and viewing the site."),
-      'type' => 'language_field',
+      'type' => 'field_item:language',
     );
     $properties['preferred_admin_langcode'] = array(
       'label' => t('Language code'),
       'description' => t("The user's preferred langcode for viewing administration pages."),
-      'type' => 'language_field',
+      'type' => 'field_item:language',
     );
     $properties['name'] = array(
       'label' => t('Name'),