diff --git a/core/modules/language/src/Plugin/migrate/source/d6/LanguageContentSettings.php b/core/modules/language/src/Plugin/migrate/source/d6/LanguageContentSettings.php
index d955fe4..a6d33d1 100644
--- a/core/modules/language/src/Plugin/migrate/source/d6/LanguageContentSettings.php
+++ b/core/modules/language/src/Plugin/migrate/source/d6/LanguageContentSettings.php
@@ -47,7 +47,7 @@ public function fields() {
   public function prepareRow(Row $row) {
     $type = $row->getSourceProperty('type');
     $row->setSourceProperty('language_content_type', $this->variableGet('language_content_type_' . $type, NULL));
-    $row->setSourceProperty('i18n_lock_node', $this->variableGet('i18n_lock_node_' . $type, NULL));
+    $row->setSourceProperty('i18n_lock_node', $this->variableGet('i18n_lock_node_' . $type, 0));
     return parent::prepareRow($row);
   }
 
diff --git a/core/modules/language/tests/src/Kernel/Migrate/d6/MigrateLanguageContentSettingsTest.php b/core/modules/language/tests/src/Kernel/Migrate/d6/MigrateLanguageContentSettingsTest.php
index c60a98d..ca382d3 100644
--- a/core/modules/language/tests/src/Kernel/Migrate/d6/MigrateLanguageContentSettingsTest.php
+++ b/core/modules/language/tests/src/Kernel/Migrate/d6/MigrateLanguageContentSettingsTest.php
@@ -2,6 +2,7 @@
 
 namespace Drupal\Tests\language\Kernel\Migrate\d6;
 
+use Drupal\Core\Language\LanguageInterface;
 use Drupal\language\Entity\ContentLanguageSettings;
 use Drupal\language\Plugin\migrate\source\d6\LanguageContentSettings;
 use Drupal\Tests\migrate_drupal\Kernel\d6\MigrateDrupal6TestBase;
@@ -47,4 +48,14 @@ public function testLanguageContent() {
     $this->assertSame($config->getDefaultLangcode(), 'site_default');
   }
 
+  /**
+   * Tests migration of content language settings when there is no language lock.
+   */
+  public function testLanguageContentWithNoLanguageLock() {
+    // Assert that a we can assign a language.
+    $config = ContentLanguageSettings::loadByEntityTypeBundle('node', 'employee');
+    $this->assertSame($config->getDefaultLangcode(), 'current_interface');
+    $this->assertTrue($config->isLanguageAlterable());
+  }
+
 }
diff --git a/core/modules/migrate_drupal/tests/fixtures/drupal6.php b/core/modules/migrate_drupal/tests/fixtures/drupal6.php
index 766244e..7d1c020 100644
--- a/core/modules/migrate_drupal/tests/fixtures/drupal6.php
+++ b/core/modules/migrate_drupal/tests/fixtures/drupal6.php
@@ -45534,6 +45534,10 @@
   'value' => 's:1:"2";',
 ))
 ->values(array(
+  'name' => 'language_content_type_employee',
+  'value' => 's:1:"2";',
+))
+->values(array(
   'name' => 'i18n_lock_node_article',
   'value' => 'i:1;',
 ))