diff -u b/core/lib/Drupal/Core/Language/LanguageManager.php b/core/lib/Drupal/Core/Language/LanguageManager.php
--- b/core/lib/Drupal/Core/Language/LanguageManager.php
+++ b/core/lib/Drupal/Core/Language/LanguageManager.php
@@ -26,7 +26,7 @@
   /**
    * An array of all the available languages keyed by language code.
    *
-   * @var array
+   * @var \Drupal\Core\Language\LanguageInterface[]
    */
   protected $languages;
 
@@ -131,7 +131,7 @@
     }
 
     foreach ($this->languages as $id => $language) {
-      if (($language->locked && ($flags & Language::STATE_LOCKED)) || (!$language->locked && ($flags & Language::STATE_CONFIGURABLE))) {
+      if (($language->isLocked() && ($flags & Language::STATE_LOCKED)) || (!$language->isLocked() && ($flags & Language::STATE_CONFIGURABLE))) {
         $filtered_languages[$id] = $language;
       }
     }
@@ -193,7 +193,7 @@
    */
   public function isLanguageLocked($langcode) {
     $language = $this->getLanguage($langcode);
-    return ($language ? $language->locked : FALSE);
+    return ($language ? $language->isLocked() : FALSE);
   }
 
   /**
only in patch2:
unchanged:
--- a/core/lib/Drupal/Core/Config/Entity/ConfigEntityStorage.php
+++ b/core/lib/Drupal/Core/Config/Entity/ConfigEntityStorage.php
@@ -256,7 +256,7 @@ public function create(array $values = array()) {
     $class::preCreate($this, $values);
 
     // Set default language to site default if not provided.
-    $values += array('langcode' => $this->languageManager->getDefaultLanguage()->id);
+    $values += array('langcode' => $this->languageManager->getDefaultLanguage()->getId());
 
     $entity = new $class($values, $this->entityTypeId);
     // Mark this entity as new, so isNew() returns TRUE. This does not check
only in patch2:
unchanged:
--- a/core/lib/Drupal/Core/Entity/ContentEntityBase.php
+++ b/core/lib/Drupal/Core/Entity/ContentEntityBase.php
@@ -553,7 +553,7 @@ public function language() {
   protected function setDefaultLangcode() {
     // Get the language code if the property exists.
     if ($this->hasField('langcode') && ($item = $this->get('langcode')) && isset($item->language)) {
-      $this->defaultLangcode = $item->language->id;
+      $this->defaultLangcode = $item->language->getId();
     }
     if (empty($this->defaultLangcode)) {
       // Make sure we return a proper language object.
only in patch2:
unchanged:
--- a/core/lib/Drupal/Core/Entity/ContentEntityDatabaseStorage.php
+++ b/core/lib/Drupal/Core/Entity/ContentEntityDatabaseStorage.php
@@ -725,9 +725,10 @@ protected function mapToStorageRecord(EntityInterface $entity, $table_key = 'bas
    *   The record to store.
    */
   protected function mapToDataStorageRecord(EntityInterface $entity, $table_key = 'data_table') {
+    /** @var \Drupal\Core\Entity\ContentEntityInterface $entity */
     $record = $this->mapToStorageRecord($entity, $table_key);
-    $record->langcode = $entity->language()->id;
-    $record->default_langcode = intval($record->langcode == $entity->getUntranslated()->language()->id);
+    $record->langcode = $entity->language()->getId();
+    $record->default_langcode = intval($record->langcode == $entity->getUntranslated()->language()->getId());
     return $record;
   }
 
@@ -775,6 +776,7 @@ public function getQueryServiceName() {
    * {@inheritdoc}
    */
   protected function doLoadFieldItems($entities, $age) {
+    /** @var \Drupal\Core\Entity\ContentEntityInterface[] $entities */
     $load_current = $age == static::FIELD_LOAD_CURRENT;
 
     // Collect entities ids, bundles and languages.
@@ -784,7 +786,7 @@ protected function doLoadFieldItems($entities, $age) {
     foreach ($entities as $key => $entity) {
       $bundles[$entity->bundle()] = TRUE;
       $ids[] = $load_current ? $key : $entity->getRevisionId();
-      $default_langcodes[$key] = $entity->getUntranslated()->language()->id;
+      $default_langcodes[$key] = $entity->getUntranslated()->language()->getId();
     }
 
     // Collect impacted fields.
@@ -844,11 +846,12 @@ protected function doLoadFieldItems($entities, $age) {
    * {@inheritdoc}
    */
   protected function doSaveFieldItems(EntityInterface $entity, $update) {
+    /** @var \Drupal\Core\Entity\ContentEntityInterface $entity */
     $vid = $entity->getRevisionId();
     $id = $entity->id();
     $bundle = $entity->bundle();
     $entity_type = $entity->getEntityTypeId();
-    $default_langcode = $entity->getUntranslated()->language()->id;
+    $default_langcode = $entity->getUntranslated()->language()->getId();
     $translation_langcodes = array_keys($entity->getTranslationLanguages());
 
     if (!isset($vid)) {
only in patch2:
unchanged:
--- a/core/lib/Drupal/Core/Page/DefaultHtmlFragmentRenderer.php
+++ b/core/lib/Drupal/Core/Page/DefaultHtmlFragmentRenderer.php
@@ -82,8 +82,8 @@ public function preparePage(HtmlPage $page, &$page_array) {
     // HTML element attributes.
     $language_interface = $this->languageManager->getCurrentLanguage();
     $html_attributes = $page->getHtmlAttributes();
-    $html_attributes['lang'] = $language_interface->id;
-    $html_attributes['dir'] = $language_interface->direction ? 'rtl' : 'ltr';
+    $html_attributes['lang'] = $language_interface->getId();
+    $html_attributes['dir'] = $language_interface->getDirection() ? 'rtl' : 'ltr';
 
     return $page;
   }
only in patch2:
unchanged:
--- a/core/lib/Drupal/Core/StringTranslation/TranslationManager.php
+++ b/core/lib/Drupal/Core/StringTranslation/TranslationManager.php
@@ -60,7 +60,7 @@ class TranslationManager implements TranslationInterface, TranslatorInterface {
    */
   public function __construct(LanguageManagerInterface $language_manager) {
     $this->languageManager = $language_manager;
-    $this->defaultLangcode = $language_manager->getDefaultLanguage()->id;
+    $this->defaultLangcode = $language_manager->getDefaultLanguage()->getId();
   }
 
   /**
only in patch2:
unchanged:
--- a/core/modules/user/user.install
+++ b/core/modules/user/user.install
@@ -227,7 +227,7 @@ function user_install() {
       'uuid' => \Drupal::service('uuid')->generate(),
       'name' => '',
       'mail' => '',
-      'langcode' => \Drupal::languageManager()->getDefaultLanguage()->id,
+      'langcode' => \Drupal::languageManager()->getDefaultLanguage()->getId(),
     ))
     ->execute();
 
@@ -241,7 +241,7 @@ function user_install() {
       'mail' => 'placeholder-for-uid-1',
       'created' => REQUEST_TIME,
       'status' => 1,
-      'langcode' => \Drupal::languageManager()->getDefaultLanguage()->id,
+      'langcode' => \Drupal::languageManager()->getDefaultLanguage()->getId(),
     ))
     ->execute();
 }