diff --git a/core/lib/Drupal/Core/Language/Language.php b/core/lib/Drupal/Core/Language/Language.php
index ec3ce71..7702496 100644
--- a/core/lib/Drupal/Core/Language/Language.php
+++ b/core/lib/Drupal/Core/Language/Language.php
@@ -80,7 +80,9 @@ class Language implements LanguageInterface {
   public function __construct(array $values = array()) {
     // Set all the provided properties for the language.
     foreach ($values as $key => $value) {
-      $this->{$key} = $value;
+      if (property_exists($this, $key)) {
+        $this->{$key} = $value;
+      }
     }
     // If some values were not set, set sane defaults of a predefined language.
     if (!isset($values['name']) || !isset($values['direction'])) {
diff --git a/core/lib/Drupal/Core/Language/LanguageManager.php b/core/lib/Drupal/Core/Language/LanguageManager.php
index 3729894..555b425 100644
--- a/core/lib/Drupal/Core/Language/LanguageManager.php
+++ b/core/lib/Drupal/Core/Language/LanguageManager.php
@@ -27,6 +27,17 @@ class LanguageManager implements LanguageManagerInterface {
   protected $translation;
 
   /**
+   * An array of arrays the available languages keyed by language code. The top
+   * level array is keyed by the language the language names are translated in.
+   * The next level is keyed by the flags provided to self::getLanguages().
+   *
+   * @var \Drupal\Core\Language\LanguageInterface[]
+   *
+   * @see \Drupal\Core\Language\LanguageManager::getLanguages()
+   */
+  protected $languages = array();
+
+  /**
    * The default language object.
    *
    * @var \Drupal\Core\Language\LanguageDefault
@@ -123,15 +134,18 @@ public function getDefaultLanguage() {
    * {@inheritdoc}
    */
   public function getLanguages($flags = LanguageInterface::STATE_CONFIGURABLE) {
-    // If this language manager is used, there are no configured languages.
-    // The default language and locked languages comprise the full language
-    // list.
-    $default = $this->getDefaultLanguage();
-    $languages = array($default->getId() => $default);
-    $languages += $this->getDefaultLockedLanguages($default->getWeight());
-
-    // Filter the full list of languages based on the value of $flags.
-    return $this->filterLanguages($languages, $flags);
+    $static_cache_id = $this->getCurrentLanguage()->getId();
+    if (!isset($this->languages[$static_cache_id][$flags])) {
+      // If this language manager is used, there are no configured languages.
+      // The default language and locked languages comprise the full language
+      // list.
+      $default = $this->getDefaultLanguage();
+      $this->languages[$static_cache_id][$flags] = array($default->getId() => $default);
+      $this->languages[$static_cache_id][$flags] += $this->getDefaultLockedLanguages($default->getWeight());
+      // Filter the full list of languages based on the value of $flags.
+      $this->languages[$static_cache_id][$flags] = $this->filterLanguages($this->languages[$static_cache_id][$flags], $flags);
+    }
+    return $this->languages[$static_cache_id][$flags];
   }
 
   /**
diff --git a/core/modules/language/src/ConfigurableLanguageManager.php b/core/modules/language/src/ConfigurableLanguageManager.php
index 2eaee36..0746696 100644
--- a/core/modules/language/src/ConfigurableLanguageManager.php
+++ b/core/modules/language/src/ConfigurableLanguageManager.php
@@ -246,6 +246,7 @@ public function reset($type = NULL) {
       $this->negotiatedMethods = array();
       $this->languageTypes = NULL;
       $this->languageTypesInfo = NULL;
+      $this->languages = array();
       if ($this->negotiator) {
         $this->negotiator->reset();
       }
@@ -277,29 +278,44 @@ public function setNegotiator(LanguageNegotiatorInterface $negotiator) {
    * {@inheritdoc}
    */
   public function getLanguages($flags = LanguageInterface::STATE_CONFIGURABLE) {
-    // Initialize the language list with the default language and default
-    // locked languages. These cannot be removed. This serves as a fallback
-    // list if this method is invoked while the language module is installed
-    // and the configuration entities for languages are not yet fully imported.
-    $languages = parent::getLanguages(LanguageInterface::STATE_ALL);
-
-    // Load configurable languages on top of the defaults. Ideally this could
-    // use the entity API to load and instantiate ConfigurableLanguage objects.
-    // However the entity API depends on the language system, so that would
-    // result in infinite loops. We use the configuration system directly and
-    // instantiate runtime Language objects. When language entities are imported
-    // those cover the default and locked languages, so site-specific
-    // configuration will prevail over the fallback values. Having them in the
-    // array already ensures if this is invoked in the middle of importing
-    // language configuration entities, the defaults are always present.
-    $config_ids = $this->configFactory->listAll('language.entity.');
-    foreach ($this->configFactory->loadMultiple($config_ids) as $config) {
-      $data = $config->get();
-      $data['name'] = $data['label'];
-      $languages[$data['id']] = new Language($data);
+    // If a config override is set cache using that language's ID.
+    if ($override_language = $this->getConfigOverrideLanguage()) {
+      $static_cache_id = $override_language->getId();
+    }
+    else {
+      $static_cache_id = $this->getCurrentLanguage()->getId();
+    }
+    if (!isset($this->languages[$static_cache_id][$flags])) {
+
+      // Initialize the language list with the default language and default
+      // locked languages. These cannot be removed. This serves as a fallback
+      // list if this method is invoked while the language module is installed
+      // and the configuration entities for languages are not yet fully imported.
+      $default = $this->getDefaultLanguage();
+      $this->languages[$static_cache_id][$flags] = array($default->getId() => $default);
+      $this->languages[$static_cache_id][$flags] += $this->getDefaultLockedLanguages($default->getWeight());
+      // Filter the full list of languages based on the value of $flags.
+      $this->languages[$static_cache_id][$flags] = $this->filterLanguages($this->languages[$static_cache_id][$flags], $flags);
+
+      // Load configurable languages on top of the defaults. Ideally this could
+      // use the entity API to load and instantiate ConfigurableLanguage objects.
+      // However the entity API depends on the language system, so that would
+      // result in infinite loops. We use the configuration system directly and
+      // instantiate runtime Language objects. When language entities are imported
+      // those cover the default and locked languages, so site-specific
+      // configuration will prevail over the fallback values. Having them in the
+      // array already ensures if this is invoked in the middle of importing
+      // language configuration entities, the defaults are always present.
+      $config_ids = $this->configFactory->listAll('language.entity.');
+      foreach ($this->configFactory->loadMultiple($config_ids) as $config) {
+        $data = $config->get();
+        $data['name'] = $data['label'];
+        $this->languages[$static_cache_id][$flags][$data['id']] = new Language($data);
+      }
+      Language::sort($this->languages[$static_cache_id][$flags]);
+      $this->languages[$static_cache_id][$flags] = $this->filterLanguages($this->languages[$static_cache_id][$flags], $flags);
     }
-    Language::sort($languages);
-    return $this->filterLanguages($languages, $flags);
+    return $this->languages[$static_cache_id][$flags];
   }
 
   /**
diff --git a/core/tests/Drupal/Tests/Core/Language/LanguageUnitTest.php b/core/tests/Drupal/Tests/Core/Language/LanguageUnitTest.php
index e21ab6f..49a9dbf 100644
--- a/core/tests/Drupal/Tests/Core/Language/LanguageUnitTest.php
+++ b/core/tests/Drupal/Tests/Core/Language/LanguageUnitTest.php
@@ -18,6 +18,20 @@
 class LanguageUnitTest extends UnitTestCase {
 
   /**
+   * @covers ::__construct
+   */
+  public function testConstruct() {
+    $name = $this->randomMachineName();
+    $language_code = $this->randomMachineName(2);
+    $uuid = $this->randomMachineName();
+    $language = new Language(array('id' => $language_code, 'name' => $name, 'uuid' => $uuid));
+    // Test that nonexistent properties are not added to the language object.
+    $this->assertTrue(property_exists($language, 'id'));
+    $this->assertTrue(property_exists($language, 'name'));
+    $this->assertFalse(property_exists($language, 'uuid'));
+  }
+
+  /**
    * @covers ::getName()
    * @covers ::setName()
    */