diff --git a/core/config/schema/core.data_types.schema.yml b/core/config/schema/core.data_types.schema.yml
index faab889..800601f 100644
--- a/core/config/schema/core.data_types.schema.yml
+++ b/core/config/schema/core.data_types.schema.yml
@@ -81,6 +81,14 @@ color_hex:
 
 # Complex extended data types:
 
+# Root of a configuration object.
+config_object:
+  type: mapping
+  mapping:
+    langcode:
+      type: string
+      label: 'Language code'
+
 # Mail text with subject and body parts.
 mail:
   type: mapping
@@ -121,7 +129,7 @@ action_configuration_default:
     type: string
 
 theme_settings:
-  type: mapping
+  type: config_object
   mapping:
     favicon:
       type: mapping
@@ -255,14 +263,11 @@ config_dependencies:
       label: 'Enforced configuration dependencies'
 
 config_entity:
-  type: mapping
+  type: config_object
   mapping:
     uuid:
       type: string
       label: 'UUID'
-    langcode:
-      type: string
-      label: 'Default language'
     status:
       type: boolean
       label: 'Status'
@@ -416,9 +421,6 @@ core.date_format.*:
     pattern:
       type: date_format
       label: 'PHP date format'
-    langcode:
-      type: string
-      label: 'Default language'
 
 # Generic field settings schemas.
 
diff --git a/core/config/schema/core.extension.schema.yml b/core/config/schema/core.extension.schema.yml
index f53e5e6..bdc84b9 100644
--- a/core/config/schema/core.extension.schema.yml
+++ b/core/config/schema/core.extension.schema.yml
@@ -1,5 +1,5 @@
 core.extension:
-  type: mapping
+  type: config_object
   label: 'Extension settings'
   mapping:
     module:
diff --git a/core/modules/config_translation/tests/modules/config_translation_test/config/schema/config_translation_test.schema.yml b/core/modules/config_translation/tests/modules/config_translation_test/config/schema/config_translation_test.schema.yml
index a5ff2e6..63b8475 100644
--- a/core/modules/config_translation/tests/modules/config_translation_test/config/schema/config_translation_test.schema.yml
+++ b/core/modules/config_translation/tests/modules/config_translation_test/config/schema/config_translation_test.schema.yml
@@ -1,7 +1,7 @@
 # Schema for the configuration files of the Configuration translation test module.
 
 config_translation_test.content:
-  type: mapping
+  type: config_object
   label: 'Content'
   mapping:
     id:
@@ -10,9 +10,6 @@ config_translation_test.content:
     label:
       type: label
       label: 'Label'
-    langcode:
-      type: string
-      label: 'Default language'
     content:
       type: text_format
       label: 'Content'
diff --git a/core/modules/filter/config/schema/filter.schema.yml b/core/modules/filter/config/schema/filter.schema.yml
index ac956f7..ab035e1 100644
--- a/core/modules/filter/config/schema/filter.schema.yml
+++ b/core/modules/filter/config/schema/filter.schema.yml
@@ -35,9 +35,6 @@ filter.format.*:
       label: 'Enabled filters'
       sequence:
         type: filter
-    langcode:
-      type: string
-      label: 'Default language'
     dependencies:
       type: config_dependencies
       label: 'Dependencies'
diff --git a/core/modules/locale/tests/modules/locale_test/config/schema/locale_test.schema.yml b/core/modules/locale/tests/modules/locale_test/config/schema/locale_test.schema.yml
index daf3391..f6cf7b9 100644
--- a/core/modules/locale/tests/modules/locale_test/config/schema/locale_test.schema.yml
+++ b/core/modules/locale/tests/modules/locale_test/config/schema/locale_test.schema.yml
@@ -1,7 +1,7 @@
 # Schema for the configuration files of the Locale Test module.
 
 locale_test.no_translation:
-  type: mapping
+  type: config_object
   label: 'No traslation settings'
   mapping:
     test:
@@ -9,11 +9,9 @@ locale_test.no_translation:
       label: 'Test'
       # See \Drupal\locale\Tests\LocaleConfigSubscriberTest
       translatable: true
-    langcode:
-      type: string
 
 locale_test.translation:
-  type: mapping
+  type: config_object
   label: 'translation settings'
   mapping:
     test:
@@ -21,5 +19,3 @@ locale_test.translation:
       label: 'Test'
       # See \Drupal\locale\Tests\LocaleConfigSubscriberTest
       translatable: true
-    langcode:
-      type: string
diff --git a/core/modules/migrate_drupal/config/schema/migrate_drupal.source.schema.yml b/core/modules/migrate_drupal/config/schema/migrate_drupal.source.schema.yml
index e43ffe8..578a169 100644
--- a/core/modules/migrate_drupal/config/schema/migrate_drupal.source.schema.yml
+++ b/core/modules/migrate_drupal/config/schema/migrate_drupal.source.schema.yml
@@ -328,7 +328,7 @@ migrate_entity_constant:
       label: 'Parent'
     langcode:
       type: string
-      label: 'Type'
+      label: 'Language code'
     third_party_settings:
       type: sequence
       label: 'Settings'
diff --git a/core/modules/system/config/schema/system.schema.yml b/core/modules/system/config/schema/system.schema.yml
index ba8fa15..3ba947e 100644
--- a/core/modules/system/config/schema/system.schema.yml
+++ b/core/modules/system/config/schema/system.schema.yml
@@ -1,7 +1,7 @@
 # Schema for the configuration files of the System module.
 
 system.site:
-  type: mapping
+  type: config_object
   label: 'Site information'
   mapping:
     uuid:
@@ -35,9 +35,6 @@ system.site:
     weight_select_max:
       type: integer
       label: 'Weight element maximum value'
-    langcode:
-      type: string
-      label: 'Language code'
     default_langcode:
       type: string
       label: 'Site default language code'
@@ -46,18 +43,15 @@ system.site:
       label: 'Notification email address'
 
 system.maintenance:
-  type: mapping
+  type: config_object
   label: 'Maintenance mode'
   mapping:
     message:
       type: text
       label: 'Message to display when in maintenance mode'
-    langcode:
-      type: string
-      label: 'Default language'
 
 system.authorize:
-  type: mapping
+  type: config_object
   label: 'Authorize settings'
   mapping:
     filetransfer_default:
@@ -65,7 +59,7 @@ system.authorize:
       label: 'Default file transfer protocol'
 
 system.cron:
-  type: mapping
+  type: config_object
   label: 'Cron settings'
   mapping:
     threshold:
@@ -83,7 +77,7 @@ system.cron:
           label: 'Requirements error period'
 
 system.date:
-  type: mapping
+  type: config_object
   label: 'Date settings'
   mapping:
     first_day:
@@ -96,9 +90,6 @@ system.date:
         default:
           type: string
           label: 'Default country'
-    langcode:
-      type: string
-      label: 'Default language'
     timezone:
       type: mapping
       label: 'Time zone settings'
@@ -121,7 +112,7 @@ system.date:
               label: 'Remind users at login if their time zone is not set'
 
 system.diff:
-  type: mapping
+  type: config_object
   label: 'Diff settings'
   mapping:
     context:
@@ -136,7 +127,7 @@ system.diff:
           label: 'Number of trailing lines in a diff'
 
 system.filter:
-  type: mapping
+  type: config_object
   label: 'Filter settings'
   mapping:
     protocols:
@@ -147,7 +138,7 @@ system.filter:
         label: 'Protocol'
 
 system.logging:
-  type: mapping
+  type: config_object
   label: 'Logging settings'
   mapping:
     error_level:
@@ -155,7 +146,7 @@ system.logging:
       label: 'Error messages to display'
 
 system.performance:
-  type: mapping
+  type: config_object
   label: 'Performance settings'
   mapping:
     cache:
@@ -220,7 +211,7 @@ system.performance:
       label: 'Stale file threshold'
 
 system.rss:
-  type: mapping
+  type: config_object
   label: 'Feed settings'
   mapping:
     channel:
@@ -240,12 +231,9 @@ system.rss:
         view_mode:
           type: string
           label: 'Feed content'
-    langcode:
-      type: string
-      label: 'Default language'
 
 system.theme:
-  type: mapping
+  type: config_object
   label: 'Theme settings'
   mapping:
     admin:
@@ -292,7 +280,7 @@ system.action.*:
       type: action.configuration.[%parent.plugin]
 
 system.file:
-  type: mapping
+  type: config_object
   label: 'File system'
   mapping:
     allow_insecure_uploads:
@@ -313,7 +301,7 @@ system.file:
       label: 'Maximum age for temporary files'
 
 system.image:
-  type: mapping
+  type: config_object
   label: 'Image settings'
   mapping:
     toolkit:
@@ -321,7 +309,7 @@ system.image:
       label: 'Toolkit'
 
 system.image.gd:
-  type: mapping
+  type: config_object
   label: 'Image settings'
   mapping:
     jpeg_quality:
@@ -329,7 +317,7 @@ system.image.gd:
       label: 'JPEG quality'
 
 system.mail:
-  type: mapping
+  type: config_object
   label: 'Mail system'
   mapping:
     interface:
diff --git a/core/modules/user/config/schema/user.schema.yml b/core/modules/user/config/schema/user.schema.yml
index 09e5989..9d853c1 100644
--- a/core/modules/user/config/schema/user.schema.yml
+++ b/core/modules/user/config/schema/user.schema.yml
@@ -1,7 +1,7 @@
 # Schema for the configuration files of the User module.
 
 user.settings:
-  type: mapping
+  type: config_object
   label: 'User settings'
   mapping:
     anonymous:
@@ -50,12 +50,9 @@ user.settings:
     password_strength:
       type: boolean
       label: 'Enable password strength indicator'
-    langcode:
-      type: string
-      label: 'Default language'
 
 user.mail:
- type: mapping
+ type: config_object
  label: 'Email settings'
  mapping:
   cancel_confirm:
@@ -85,12 +82,9 @@ user.mail:
   status_canceled:
     type: mail
     label: 'Account cancelled'
-  langcode:
-    type: string
-    label: 'Default language'
 
 user.flood:
-  type: mapping
+  type: config_object
   label: 'User flood settings'
   mapping:
     uid_only: