diff --git a/core/lib/Drupal/Core/Config/Entity/ConfigStorageController.php b/core/lib/Drupal/Core/Config/Entity/ConfigStorageController.php
index dd4c028a6b58..5487e04d0a62 100644
--- a/core/lib/Drupal/Core/Config/Entity/ConfigStorageController.php
+++ b/core/lib/Drupal/Core/Config/Entity/ConfigStorageController.php
@@ -284,6 +284,9 @@ class ConfigStorageController implements EntityStorageControllerInterface {
   public function create(array $values) {
     $class = $this->entityInfo['class'];
 
+    // Set default language to site default if not provided.
+    $values += array('langcode' => language_default()->langcode);
+
     $entity = new $class($values, $this->entityType);
     // Mark this entity as new, so isNew() returns TRUE. This does not check
     // whether a configuration entity with the same ID (if any) already exists.
diff --git a/core/lib/Drupal/Core/Entity/EntityFormController.php b/core/lib/Drupal/Core/Entity/EntityFormController.php
index 4a03975c2c50..6d2c9fb8ca34 100644
--- a/core/lib/Drupal/Core/Entity/EntityFormController.php
+++ b/core/lib/Drupal/Core/Entity/EntityFormController.php
@@ -80,6 +80,15 @@ class EntityFormController implements EntityFormControllerInterface {
     if (!empty($info['fieldable'])) {
       field_attach_form($entity, $form, $form_state, $this->getFormLangcode($form_state));
     }
+    if (!isset($form['langcode'])) {
+      // If the form did not specify otherwise, default to keeping the existing
+      // language of the entity or defaulting to the site default language for
+      // new entities.
+      $form['langcode'] = array(
+        '#type' => 'value',
+        '#value' => !$entity->isNew() ? $entity->langcode : language_default()->langcode,
+      );
+    }
     return $form;
   }
 
diff --git a/core/modules/block/custom_block/config/custom_block.type.basic.yml b/core/modules/block/custom_block/config/custom_block.type.basic.yml
index 1b0e2f8dc534..58e87d757bcd 100644
--- a/core/modules/block/custom_block/config/custom_block.type.basic.yml
+++ b/core/modules/block/custom_block/config/custom_block.type.basic.yml
@@ -2,3 +2,4 @@ id: basic
 label: Basic block
 revision: '0'
 description: A basic block contains a title and a body.
+langcode: en
diff --git a/core/modules/block/custom_block/lib/Drupal/custom_block/Tests/CustomBlockTypeTest.php b/core/modules/block/custom_block/lib/Drupal/custom_block/Tests/CustomBlockTypeTest.php
index d94e47638cd9..eee184adbb16 100644
--- a/core/modules/block/custom_block/lib/Drupal/custom_block/Tests/CustomBlockTypeTest.php
+++ b/core/modules/block/custom_block/lib/Drupal/custom_block/Tests/CustomBlockTypeTest.php
@@ -64,6 +64,10 @@ class CustomBlockTypeTest extends CustomBlockTestBase {
     $this->drupalPost('admin/structure/custom-blocks/add', $edit, t('Save'));
     $block_type = entity_load('custom_block_type', 'foo');
     $this->assertTrue($block_type, 'The new block type has been created.');
+
+    // Check that the block type was created in site default language.
+    $default_langcode = language_default()->langcode;
+    $this->assertEqual($block_type->langcode, $default_langcode);
   }
 
   /**
diff --git a/core/modules/block/lib/Drupal/block/Tests/BlockStorageUnitTest.php b/core/modules/block/lib/Drupal/block/Tests/BlockStorageUnitTest.php
index 490e434fa829..207f20bd001f 100644
--- a/core/modules/block/lib/Drupal/block/Tests/BlockStorageUnitTest.php
+++ b/core/modules/block/lib/Drupal/block/Tests/BlockStorageUnitTest.php
@@ -104,7 +104,7 @@ class BlockStorageUnitTest extends DrupalUnitTestBase {
         'cache' => '1',
         'admin_label' => t('Test block html id'),
       ),
-      'langcode' => LANGUAGE_NOT_SPECIFIED,
+      'langcode' => language_default()->langcode,
     );
     $this->assertIdentical($actual_properties, $expected_properties, 'The block properties are exported correctly.');
 
diff --git a/core/modules/config/lib/Drupal/config/Tests/ConfigEntityTest.php b/core/modules/config/lib/Drupal/config/Tests/ConfigEntityTest.php
index 90ae934d33c1..84fbc97b8230 100644
--- a/core/modules/config/lib/Drupal/config/Tests/ConfigEntityTest.php
+++ b/core/modules/config/lib/Drupal/config/Tests/ConfigEntityTest.php
@@ -35,13 +35,14 @@ class ConfigEntityTest extends WebTestBase {
    */
   function testCRUD() {
     $manifest_name = 'manifest.config_test.dynamic';
+    $default_langcode = language_default()->langcode;
     // Verify default properties on a newly created empty entity.
     $empty = entity_create('config_test', array());
     $this->assertIdentical($empty->id, NULL);
     $this->assertTrue($empty->uuid);
     $this->assertIdentical($empty->label, NULL);
     $this->assertIdentical($empty->style, NULL);
-    $this->assertIdentical($empty->langcode, LANGUAGE_NOT_SPECIFIED);
+    $this->assertIdentical($empty->langcode, $default_langcode);
 
     // Verify ConfigEntity properties/methods on the newly created empty entity.
     $this->assertIdentical($empty->isNew(), TRUE);
@@ -55,7 +56,7 @@ class ConfigEntityTest extends WebTestBase {
     $this->assertTrue($empty->get('uuid'));
     $this->assertIdentical($empty->get('label'), NULL);
     $this->assertIdentical($empty->get('style'), NULL);
-    $this->assertIdentical($empty->get('langcode'), LANGUAGE_NOT_SPECIFIED);
+    $this->assertIdentical($empty->get('langcode'), $default_langcode);
 
     // Verify Entity properties/methods on the newly created empty entity.
     $this->assertIdentical($empty->isNewRevision(), FALSE);
@@ -97,7 +98,7 @@ class ConfigEntityTest extends WebTestBase {
     $this->assertNotEqual($config_test->uuid, $empty->uuid);
     $this->assertIdentical($config_test->label, $expected['label']);
     $this->assertIdentical($config_test->style, $expected['style']);
-    $this->assertIdentical($config_test->langcode, LANGUAGE_NOT_SPECIFIED);
+    $this->assertIdentical($config_test->langcode, $default_langcode);
 
     // Verify methods on the newly created entity.
     $this->assertIdentical($config_test->isNew(), TRUE);
diff --git a/core/modules/config/lib/Drupal/config/Tests/ConfigImportTest.php b/core/modules/config/lib/Drupal/config/Tests/ConfigImportTest.php
index 9278269d10db..03fda2a77c70 100644
--- a/core/modules/config/lib/Drupal/config/Tests/ConfigImportTest.php
+++ b/core/modules/config/lib/Drupal/config/Tests/ConfigImportTest.php
@@ -110,7 +110,7 @@ class ConfigImportTest extends DrupalUnitTestBase {
       'label' => 'New',
       'style' => '',
       'status' => '1',
-      'langcode' => 'und',
+      'langcode' => language_default()->langcode,
       'protected_property' => '',
     );
     $staging->write($dynamic_name, $original_dynamic_data);
diff --git a/core/modules/config/lib/Drupal/config/Tests/ConfigImportUITest.php b/core/modules/config/lib/Drupal/config/Tests/ConfigImportUITest.php
index 3788d67c92b3..cf87bb396559 100644
--- a/core/modules/config/lib/Drupal/config/Tests/ConfigImportUITest.php
+++ b/core/modules/config/lib/Drupal/config/Tests/ConfigImportUITest.php
@@ -61,7 +61,7 @@ class ConfigImportUITest extends WebTestBase {
       'label' => 'New',
       'style' => '',
       'status' => '1',
-      'langcode' => 'und',
+      'langcode' => language_default()->langcode,
       'protected_property' => '',
     );
     $staging->write($dynamic_name, $original_dynamic_data);
diff --git a/core/modules/contact/config/contact.category.feedback.yml b/core/modules/contact/config/contact.category.feedback.yml
index 8aff8c61c25f..aae9098cb2b4 100644
--- a/core/modules/contact/config/contact.category.feedback.yml
+++ b/core/modules/contact/config/contact.category.feedback.yml
@@ -3,3 +3,4 @@ label: 'Website feedback'
 recipients: []
 reply: ''
 weight: '0'
+langcode: en
diff --git a/core/modules/contact/lib/Drupal/contact/Tests/ContactSitewideTest.php b/core/modules/contact/lib/Drupal/contact/Tests/ContactSitewideTest.php
index bdc98efe9b4c..1ea830b49a4e 100644
--- a/core/modules/contact/lib/Drupal/contact/Tests/ContactSitewideTest.php
+++ b/core/modules/contact/lib/Drupal/contact/Tests/ContactSitewideTest.php
@@ -82,6 +82,11 @@ class ContactSitewideTest extends WebTestBase {
     $this->addCategory($id = drupal_strtolower($this->randomName(16)), $label = $this->randomName(16), implode(',', array($recipients[0])), '', TRUE);
     $this->assertRaw(t('Category %label has been added.', array('%label' => $label)));
 
+    // Check that the category was created in site default language.
+    $langcode = config('contact.category.' . $id)->get('langcode');
+    $default_langcode = language_default()->langcode;
+    $this->assertEqual($langcode, $default_langcode);
+
     // Make sure the newly created category is included in the list of categories.
     $this->assertNoUniqueText($label, 'New category included in categories list.');
 
diff --git a/core/modules/filter/filter.admin.inc b/core/modules/filter/filter.admin.inc
index e78ce67dacc0..aa3018cf175c 100644
--- a/core/modules/filter/filter.admin.inc
+++ b/core/modules/filter/filter.admin.inc
@@ -169,6 +169,11 @@ function filter_admin_format_form($form, &$form_state, $format) {
     '#disabled' => !empty($format->format),
     '#weight' => -20,
   );
+  // @todo Remove once moved to FilterFormatFormController.
+  $form['langcode'] = array(
+    '#type' => 'value',
+    '#value' => !$format->isNew() ? $format->langcode : language_default()->langcode,
+  );
 
   // Add user role access selection.
   $form['roles'] = array(
diff --git a/core/modules/filter/lib/Drupal/filter/Tests/FilterCrudTest.php b/core/modules/filter/lib/Drupal/filter/Tests/FilterCrudTest.php
index 21dcbf091ec4..7ba7b7da5c56 100644
--- a/core/modules/filter/lib/Drupal/filter/Tests/FilterCrudTest.php
+++ b/core/modules/filter/lib/Drupal/filter/Tests/FilterCrudTest.php
@@ -84,6 +84,7 @@ class FilterCrudTest extends WebTestBase {
    */
   function verifyTextFormat($format) {
     $t_args = array('%format' => $format->name);
+    $default_langcode = language_default()->langcode;
 
     // Verify filter_format_load().
     $filter_format = filter_format_load($format->format);
@@ -91,6 +92,8 @@ class FilterCrudTest extends WebTestBase {
     $this->assertEqual($filter_format->name, $format->name, format_string('filter_format_load: Proper title for text format %format.', $t_args));
     $this->assertEqual($filter_format->cache, $format->cache, format_string('filter_format_load: Proper cache indicator for text format %format.', $t_args));
     $this->assertEqual($filter_format->weight, $format->weight, format_string('filter_format_load: Proper weight for text format %format.', $t_args));
+    // Check that the filter was created in site default language.
+    $this->assertEqual($format->langcode, $default_langcode, format_string('filter_format_load: Proper language code for text format %format.', $t_args));
 
     // Verify the 'cache' text format property according to enabled filters.
     $filter_info = filter_get_filters();
diff --git a/core/modules/user/config/user.role.anonymous.yml b/core/modules/user/config/user.role.anonymous.yml
index 11defb06f093..1947f35310c3 100644
--- a/core/modules/user/config/user.role.anonymous.yml
+++ b/core/modules/user/config/user.role.anonymous.yml
@@ -1,3 +1,4 @@
 id: anonymous
 label: Anonymous user
 weight: 0
+langcode: en
diff --git a/core/modules/user/config/user.role.authenticated.yml b/core/modules/user/config/user.role.authenticated.yml
index dc4b65d6311d..16df96d3c981 100644
--- a/core/modules/user/config/user.role.authenticated.yml
+++ b/core/modules/user/config/user.role.authenticated.yml
@@ -1,3 +1,4 @@
 id: authenticated
 label: Authenticated user
 weight: 1
+langcode: en
diff --git a/core/modules/user/lib/Drupal/user/Tests/UserRoleAdminTest.php b/core/modules/user/lib/Drupal/user/Tests/UserRoleAdminTest.php
index d322a6407431..0025873d169b 100644
--- a/core/modules/user/lib/Drupal/user/Tests/UserRoleAdminTest.php
+++ b/core/modules/user/lib/Drupal/user/Tests/UserRoleAdminTest.php
@@ -32,6 +32,7 @@ class UserRoleAdminTest extends WebTestBase {
    */
   function testRoleAdministration() {
     $this->drupalLogin($this->admin_user);
+    $default_langcode = language_default()->langcode;
 
     // Test adding a role. (In doing so, we use a role name that happens to
     // correspond to an integer, to test that the role administration pages
@@ -43,6 +44,9 @@ class UserRoleAdminTest extends WebTestBase {
     $role = entity_load('user_role', $role_name);
     $this->assertTrue(is_object($role), 'The role was successfully retrieved from the database.');
 
+    // Check that the role was created in site default language.
+    $this->assertEqual($role->langcode, $default_langcode);
+
     // Try adding a duplicate role.
     $this->drupalPost(NULL, $edit, t('Add role'));
     $this->assertRaw(t('The machine-readable name is already in use. It must be unique.'), 'Duplicate role warning displayed.');
diff --git a/core/modules/user/user.admin.inc b/core/modules/user/user.admin.inc
index c3931d8490d4..882cef2dd1bf 100644
--- a/core/modules/user/user.admin.inc
+++ b/core/modules/user/user.admin.inc
@@ -1004,6 +1004,11 @@ function user_admin_role($form, $form_state, $role) {
       'source' => array('role', 'label'),
     ),
   );
+  // @todo Remove once moved to RoleFormController.
+  $form['role']['langcode'] = array(
+    '#type' => 'value',
+    '#value' => !$role->isNew() ? $role->langcode : language_default()->langcode,
+  );
   $form['role']['weight'] = array(
     '#type' => 'value',
     '#value' => $role->weight,