diff --git a/core/includes/language.inc b/core/includes/language.inc
index 2af9312..aa6f225 100644
--- a/core/includes/language.inc
+++ b/core/includes/language.inc
@@ -56,7 +56,10 @@
  *   unset($language_types[Language::TYPE_CONTENT]['fixed']);
  * }
  * @endcode
- * @todo Fix documentation with the locked parameter.
+ *
+ * The locked configuration property prevents one language type from being
+ * switched from customized to not customized, and vice versa.
+ * @see language_types_set()
  *
  * Every language type can have a different set of language negotiation methods
  * assigned to it. Different language types often share the same language
@@ -207,13 +210,12 @@ function language_types_disable($types) {
  * @param array $configurable
  *   The configuration object containing the user defined preferences for
  *   language type customizability.
- * @todo
- *   We are using variable_set('language_types', $language_types) and
+ * @todo We are using variable_set('language_types', $language_types) and
  *   config('system.language.types')->set('configurable', $configurable)->save()
  *   at the same time. This is redundant. We need to change variable_set to
- *   configuration.
+ *   configuration in http://drupal.org/node/2010542.
  */
-function language_types_set($configurable) {
+function language_types_set(array $configurable) {
   // Ensure that we are getting the defined language negotiation information. An
   // invocation of module_enable() or module_disable() could outdate the cached
   // information.
diff --git a/core/modules/language/language.admin.inc b/core/modules/language/language.admin.inc
index 450d3f2..424163e 100644
--- a/core/modules/language/language.admin.inc
+++ b/core/modules/language/language.admin.inc
@@ -363,7 +363,7 @@ function language_negotiation_configure_form() {
   $form['#language_types'] = array();
   $configurable = config('system.language.types')->get('configurable');
   foreach ($form['#language_types_info'] as $type => $info) {
-    // Show locked language types only if they they are configurable.
+    // Show locked language types only if they are configurable.
     if (empty($info['locked']) || $configurable[$type]) {
       $form['#language_types'][] = $type;
     }
@@ -980,11 +980,11 @@ function language_content_settings_form_submit(array $form, array &$form_state)
 /**
  * Helper function to disable the language switcher blocks.
  *
- * @param $language_types
+ * @param array $language_types
  *   Array containing all language types whose language switchers need to be
  *   disabled.
  */
-function _language_disable_language_switcher($language_types) {
+function _language_disable_language_switcher(array $language_types) {
   $blocks = _block_rehash();
   foreach ($language_types as $language_type) {
     foreach ($blocks as $block) {
diff --git a/core/modules/language/language.admin.js b/core/modules/language/language.admin.js
index dda9a65..7e974b0 100644
--- a/core/modules/language/language.admin.js
+++ b/core/modules/language/language.admin.js
@@ -18,7 +18,7 @@ Drupal.behaviors.negotiationLanguage = {
         .find('table, .tabledrag-toggle-weight')
           .toggle($checkbox.prop('checked'));
     }
-    // Bind hide/show + rearrange to customization checkboxes.
+    // Bind hide/show and rearrange customization checkboxes.
     $configForm.once('negotiation-language-admin-bind').on('change', inputSelector, function (event) {
       toggleTable(event.target);
     });
diff --git a/core/modules/language/tests/language_test/language_test.module b/core/modules/language/tests/language_test/language_test.module
index bbb719e..bce9783 100644
--- a/core/modules/language/tests/language_test/language_test.module
+++ b/core/modules/language/tests/language_test/language_test.module
@@ -45,7 +45,8 @@ function language_test_language_types_info_alter(array &$language_types) {
   if (state()->get('language_test.content_language_type')) {
     $language_types[Language::TYPE_CONTENT]['locked'] = FALSE;
     unset($language_types[Language::TYPE_CONTENT]['fixed']);
-    // By default languages are not configurable. Make LANGUAGE_TYPE_CONTENT configurable.
+    // By default languages are not configurable. Make LANGUAGE_TYPE_CONTENT
+    // configurable.
     $configurable = config('system.language.types')->get('configurable');
     $configurable[Language::TYPE_CONTENT] = TRUE;
     config('system.language.types')->set('configurable', $configurable)->save();
diff --git a/core/modules/translation_entity/translation_entity.module b/core/modules/translation_entity/translation_entity.module
index ef94176..0aa5981 100644
--- a/core/modules/translation_entity/translation_entity.module
+++ b/core/modules/translation_entity/translation_entity.module
@@ -63,8 +63,8 @@ function translation_entity_module_implements_alter(&$implementations, $hook) {
  * Implements hook_language_type_info_alter().
  */
 function translation_entity_language_types_info_alter(array &$language_types) {
-  // Make content language negotiation configurable by removing unsetting the
-  // 'locked' flag.
+  // Make content language negotiation configurable by removing the 'locked'
+  // flag.
   $language_types[Language::TYPE_CONTENT]['locked'] = FALSE;
   unset($language_types[Language::TYPE_CONTENT]['fixed']);
 }