diff --git a/core/modules/language/language.module b/core/modules/language/language.module
index e92baa24904..6d9f6994084 100644
--- a/core/modules/language/language.module
+++ b/core/modules/language/language.module
@@ -311,8 +311,13 @@ function language_negotiation_url_domains() {
  */
 function language_modules_installed($modules) {
   if (!in_array('language', $modules)) {
+    // Since newly (un)installed modules may change the default settings for
+    // non-locked language types (e.g. content language), we need to resave the
+    // language type configuration.
+    /** @var \Drupal\language\LanguageNegotiatorInterface $negotiator */
     $negotiator = \Drupal::service('language_negotiator');
-    $negotiator->updateConfiguration(array());
+    $configurable = \Drupal::config('language.types')->get('configurable');
+    $negotiator->updateConfiguration($configurable);
     $negotiator->purgeConfiguration();
   }
   else {
diff --git a/core/modules/language/src/Tests/LanguageNegotiationInfoTest.php b/core/modules/language/src/Tests/LanguageNegotiationInfoTest.php
index 8ef3c098434..511c1474530 100644
--- a/core/modules/language/src/Tests/LanguageNegotiationInfoTest.php
+++ b/core/modules/language/src/Tests/LanguageNegotiationInfoTest.php
@@ -23,14 +23,14 @@ class LanguageNegotiationInfoTest extends WebTestBase {
    *
    * @var array
    */
-  public static $modules = array('language');
+  public static $modules = ['language', 'content_translation'];
 
   /**
    * {@inheritdoc}
    */
   protected function setUp() {
     parent::setUp();
-    $admin_user = $this->drupalCreateUser(array('administer languages', 'access administration pages', 'view the administration theme'));
+    $admin_user = $this->drupalCreateUser(['administer languages', 'access administration pages', 'view the administration theme', 'administer modules']);
     $this->drupalLogin($admin_user);
     $this->drupalPostForm('admin/config/regional/language/add', array('predefined_langcode' => 'it'), t('Add language'));
   }
@@ -174,4 +174,41 @@ class LanguageNegotiationInfoTest extends WebTestBase {
       }
     }
   }
+
+  /**
+   * Tests altering config of configurable language types.
+   */
+  public function testConfigLangTypeAlterations() {
+    // Default of config.
+    $test_type = LanguageInterface::TYPE_CONTENT;
+    $this->assertFalse($this->isLanguageTypeConfigurable($test_type), 'Language type is not configurable.');
+
+    // Editing config.
+    $edit = [$test_type . '[configurable]' => TRUE];
+    $this->drupalPostForm('admin/config/regional/language/detection', $edit, t('Save settings'));
+    $this->assertTrue($this->isLanguageTypeConfigurable($test_type), 'Language type is now configurable.');
+
+    // After installing another module, the config should be the same.
+    $this->drupalPostForm('admin/modules', ['modules[Testing][test_module][enable]' => 1], t('Install'));
+    $this->assertTrue($this->isLanguageTypeConfigurable($test_type), 'Language type is still configurable.');
+
+    // After uninstalling the other module, the config should be the same.
+    $this->drupalPostForm('admin/modules/uninstall', ['uninstall[test_module]' => 1], t('Uninstall'));
+    $this->assertTrue($this->isLanguageTypeConfigurable($test_type), 'Language type is still configurable.');
+  }
+
+  /**
+   * Checks whether the given language type is configurable.
+   *
+   * @param string $type
+   *   The language type.
+   *
+   * @return bool
+   *   TRUE if the specified language type is configurable, FALSE otherwise.
+   */
+  protected function isLanguageTypeConfigurable($type) {
+    $configurable_types = $this->config('language.types')->get('configurable');
+    return in_array($type, $configurable_types);
+  }
+
 }
diff --git a/core/modules/language/tests/test_module/test_module.info.yml b/core/modules/language/tests/test_module/test_module.info.yml
new file mode 100644
index 00000000000..f68226f86b1
--- /dev/null
+++ b/core/modules/language/tests/test_module/test_module.info.yml
@@ -0,0 +1,6 @@
+name: 'Test Module'
+type: module
+description: 'Support module for testing.'
+package: Testing
+version: VERSION
+core: 8.x