diff --git a/core/lib/Drupal/Core/Config/ConfigImportValidateEventSubscriberBase.php b/core/lib/Drupal/Core/Config/ConfigImportValidateEventSubscriberBase.php
index 2b8b6f6..e907259 100644
--- a/core/lib/Drupal/Core/Config/ConfigImportValidateEventSubscriberBase.php
+++ b/core/lib/Drupal/Core/Config/ConfigImportValidateEventSubscriberBase.php
@@ -33,7 +33,7 @@ public function __construct(TranslationInterface $translation_manager) {
   }
 
   /**
-   * Checks that the configuration synchronisation is valid.
+   * Checks that the configuration synchronization is valid.
    *
    * @param ConfigImporterEvent $event
    *   The config import event.
diff --git a/core/lib/Drupal/Core/Config/ConfigImporter.php b/core/lib/Drupal/Core/Config/ConfigImporter.php
index ade9260..2ccbf94 100644
--- a/core/lib/Drupal/Core/Config/ConfigImporter.php
+++ b/core/lib/Drupal/Core/Config/ConfigImporter.php
@@ -138,8 +138,8 @@ class ConfigImporter extends DependencySerialization {
    * A log of any errors encountered.
    *
    * If errors are logged during the validation event the configuration
-   * synchronisation will not occur. If errors occur during an import then best
-   * efforts are made to complete the synchronisation.
+   * synchronization will not occur. If errors occur during an import then best
+   * efforts are made to complete the synchronization.
    *
    * @var array
    */
@@ -670,7 +670,7 @@ public function validate() {
     if (!$this->validated) {
       $this->eventDispatcher->dispatch(ConfigEvents::IMPORT_VALIDATE, new ConfigImporterEvent($this));
       if (count($this->getErrors())) {
-        throw new ConfigImporterException('There were errors validating the config synchronisation.');
+        throw new ConfigImporterException('There were errors validating the config synchronization.');
       }
       else {
         $this->validated = TRUE;
diff --git a/core/modules/config/lib/Drupal/config/Form/ConfigSync.php b/core/modules/config/lib/Drupal/config/Form/ConfigSync.php
index f8d4c94..a505a6c 100644
--- a/core/modules/config/lib/Drupal/config/Form/ConfigSync.php
+++ b/core/modules/config/lib/Drupal/config/Form/ConfigSync.php
@@ -277,7 +277,7 @@ public function submitForm(array &$form, array &$form_state) {
       }
       catch (ConfigImporterException $e) {
         // There are validation errors.
-        drupal_set_message($this->t('The configuration synchronisation failed validation.'));
+        drupal_set_message($this->t('The configuration synchronization failed validation.'));
         foreach ($config_importer->getErrors() as $message) {
           drupal_set_message($message, 'error');
         }
diff --git a/core/modules/config/lib/Drupal/config/Tests/ConfigImportUITest.php b/core/modules/config/lib/Drupal/config/Tests/ConfigImportUITest.php
index 45de6da..53954c7 100644
--- a/core/modules/config/lib/Drupal/config/Tests/ConfigImportUITest.php
+++ b/core/modules/config/lib/Drupal/config/Tests/ConfigImportUITest.php
@@ -323,7 +323,7 @@ public function testImportValidation() {
     $this->drupalPostForm(NULL, array(), t('Import all'));
 
     // Verify that the validation messages appear.
-    $this->assertText('The configuration synchronisation failed validation.');
+    $this->assertText('The configuration synchronization failed validation.');
     $this->assertText('Config import validate error 1.');
     $this->assertText('Config import validate error 2.');
 
diff --git a/core/modules/config/lib/Drupal/config/Tests/ConfigImporterTest.php b/core/modules/config/lib/Drupal/config/Tests/ConfigImporterTest.php
index db2166c..341d3d4 100644
--- a/core/modules/config/lib/Drupal/config/Tests/ConfigImporterTest.php
+++ b/core/modules/config/lib/Drupal/config/Tests/ConfigImporterTest.php
@@ -114,7 +114,7 @@ function testSiteUuidValidate() {
       $this->assertFalse(FALSE, 'ConfigImporterException not thrown, invalid import was not stopped due to mis-matching site UUID.');
     }
     catch (ConfigImporterException $e) {
-      $this->assertEqual($e->getMessage(), 'There were errors validating the config synchronisation.');
+      $this->assertEqual($e->getMessage(), 'There were errors validating the config synchronization.');
       $error_log = $this->configImporter->getErrors();
       $expected = array('Site UUID in source storage does not match the target storage.');
       $this->assertEqual($expected, $error_log);
diff --git a/core/modules/system/lib/Drupal/system/SystemConfigSubscriber.php b/core/modules/system/lib/Drupal/system/SystemConfigSubscriber.php
index 3445fe8..765b824 100644
--- a/core/modules/system/lib/Drupal/system/SystemConfigSubscriber.php
+++ b/core/modules/system/lib/Drupal/system/SystemConfigSubscriber.php
@@ -17,7 +17,7 @@
 class SystemConfigSubscriber extends ConfigImportValidateEventSubscriberBase {
 
   /**
-   * Checks that the configuration synchronisation is valid.
+   * Checks that the configuration synchronization is valid.
    *
    * This event listener implements two checks:
    *   - prevents deleting all configuration.