diff --git a/core/lib/Drupal/Core/Field/Plugin/Field/FieldType/LanguageItem.php b/core/lib/Drupal/Core/Field/Plugin/Field/FieldType/LanguageItem.php
index b7ce7fb..fda89e3 100644
--- a/core/lib/Drupal/Core/Field/Plugin/Field/FieldType/LanguageItem.php
+++ b/core/lib/Drupal/Core/Field/Plugin/Field/FieldType/LanguageItem.php
@@ -44,6 +44,8 @@ class LanguageItem extends FieldItemBase {
   public static function propertyDefinitions(FieldStorageDefinitionInterface $field_definition) {
     $properties['value'] = DataDefinition::create('string')
       ->setLabel(t('Language code'))
+      // @todo This setting is currently being ignored for language field items,
+      // fix this.
       ->setSetting('is_ascii', TRUE)
       ->setRequired(TRUE);
 
@@ -74,9 +76,9 @@ public static function schema(FieldStorageDefinitionInterface $field_definition)
     return array(
       'columns' => array(
         'value' => array(
+          // @todo Turn this into varchar_ascii.
           'type' => 'varchar',
           'length' => 12,
-          'is_ascii' => TRUE,
         ),
       ),
     );
diff --git a/core/modules/system/src/Tests/Entity/Update/SqlContentEntityStorageSchemaIndexTest.php b/core/modules/system/src/Tests/Entity/Update/SqlContentEntityStorageSchemaIndexTest.php
index 0e613f1..370e407 100644
--- a/core/modules/system/src/Tests/Entity/Update/SqlContentEntityStorageSchemaIndexTest.php
+++ b/core/modules/system/src/Tests/Entity/Update/SqlContentEntityStorageSchemaIndexTest.php
@@ -77,6 +77,11 @@ public function testIndex() {
 
     // User update were not run during update_order_test_update_8002().
     $this->assertFalse(\Drupal::state()->get('update_order_test_update_8002_user__id__default_langcode__langcode', TRUE));
+
+    // There should be no remaining updates.
+    $this->runUpdates();
+    $change_summary = \Drupal::service('entity.definition_update_manager')->getChangeSummary();
+    $this->assertTrue(empty($change_summary), 'No more pending entity updates found');
   }
 
 }
diff --git a/core/modules/system/system.install b/core/modules/system/system.install
index f38af8a..cf86940 100644
--- a/core/modules/system/system.install
+++ b/core/modules/system/system.install
@@ -1241,3 +1241,48 @@ function system_update_8003() {
     ]
   );
 }
+
+/**
+ * Remove the is_ascii key from langcode columns in schema definitions.
+ */
+function system_update_8004() {
+  $schema = \Drupal::keyValue('entity.storage_schema.sql')->getAll();
+  $schema_copy = $schema;
+  foreach ($schema as $item_name => $item) {
+    foreach ($item as $table_name => $table_schema) {
+      foreach ($table_schema as $schema_key => $schema_data) {
+        if ($schema_key == 'fields') {
+          foreach ($schema_data as $field_name => $field_data) {
+            foreach ($field_data as $field_data_property => $field_data_value) {
+              if ($field_data_property == 'is_ascii') {
+                unset($schema_copy[$item_name][$table_name][$schema_key][$field_name][$field_data_property]);
+              }
+            }
+          }
+        }
+      }
+
+    }
+  }
+  \Drupal::keyValue('entity.storage_schema.sql')->setMultiple($schema_copy);
+
+  $definitions = \Drupal::keyValue('entity.definitions.installed')->getAll();
+  $definitions_copy = $definitions;
+  foreach ($definitions as $item_name => $item_value) {
+    $suffix = '.field_storage_definitions';
+    if (substr($item_name, -strlen($suffix)) == $suffix) {
+      foreach ($item_value as $field_name => $field_definition) {
+        $reflection = new \ReflectionObject($field_definition);
+        $schema_property = $reflection->getProperty('schema');
+        $schema_property->setAccessible(TRUE);
+        $schema = $schema_property->getValue($field_definition);
+        unset($schema['columns']['value']['is_ascii']);
+        $schema_property->setValue($field_definition, $schema);
+        $schema_property->setAccessible(FALSE);
+        $definitions_copy[$item_name][$field_name] = $field_definition;
+      }
+    }
+  }
+  \Drupal::keyValue('entity.definitions.installed')->setMultiple($definitions_copy);
+}
+