diff --git a/core/modules/language/lib/Drupal/language/LanguageConfigContext.php b/core/lib/Drupal/Core/Config/Context/LanguageConfigContext.php
similarity index 78%
rename from core/modules/language/lib/Drupal/language/LanguageConfigContext.php
rename to core/lib/Drupal/Core/Config/Context/LanguageConfigContext.php
index 58b83a6df9b104305ec781012d0f075c2d9f8122..ab65df113eb434b0d1dce8c7d4ba8d7b53f63b92 100644
--- a/core/modules/language/lib/Drupal/language/LanguageConfigContext.php
+++ b/core/lib/Drupal/Core/Config/Context/LanguageConfigContext.php
@@ -2,21 +2,19 @@
 
 /**
  * @file
- * Contains \Drupal\language\LanguageConfigContext.
+ * Contains \Drupal\Core\Config\Context\LanguageConfigContext.
  */
 
-namespace Drupal\language;
+namespace Drupal\Core\Config\Context;
 
 use Drupal\Core\Config\Context\ConfigContext;
 use Drupal\Core\Language\Language;
 
-
 /**
  * Defines a configuration context object for a language.
  *
  * This should be used when configuration objects need a context for a language
  * other than the current language.
- *
  */
 class LanguageConfigContext extends ConfigContext {
 
@@ -29,14 +27,15 @@ class LanguageConfigContext extends ConfigContext {
    * Creates the configuration context for language.
    *
    * @param \Drupal\Core\Language\Language $language
-   *   The language to add to the config context.
+   *   The language object to add to the config context.
    *
    * @return \Drupal\Core\Language\Language
-   *   The language config context object.
+   *   The config context language object.
    */
   public function setLanguage(Language $language) {
     $this->set(self::LANGUAGE_KEY, $language);
-    // Re-initialize since the language change changes the context fundamentally.
+    // Re-initialize since the language change changes the context
+    // fundamentally.
     $this->init();
     return $this;
   }
diff --git a/core/lib/Drupal/Core/Datetime/Date.php b/core/lib/Drupal/Core/Datetime/Date.php
index dbd3dcfd40e9b7e2c100f0de717a57d0b14d9c1d..ed6db12c4c684315afca30185bed4072d3d1426e 100644
--- a/core/lib/Drupal/Core/Datetime/Date.php
+++ b/core/lib/Drupal/Core/Datetime/Date.php
@@ -110,13 +110,13 @@ public function format($timestamp, $type = 'medium', $format = '', $timezone = N
     $key = $date->canUseIntl() ? DrupalDateTime::INTL : DrupalDateTime::PHP;
 
     // If we have a non-custom date format use the provided date format pattern.
-    if ($date_format = $this->dateFormat($type)) {
+    if ($date_format = $this->dateFormat($type, $langcode)) {
       $format = $date_format->getPattern($key);
     }
 
     // Fall back to medium if a format was not found.
     if (empty($format)) {
-      $format = $this->dateFormat('fallback')->getPattern($key);
+      $format = $this->dateFormat('fallback', $langcode)->getPattern($key);
     }
 
     // Call $date->format().
@@ -127,11 +127,27 @@ public function format($timestamp, $type = 'medium', $format = '', $timezone = N
     return Xss::filter($date->format($format, $settings));
   }
 
-  protected function dateFormat($format) {
-    if (!isset($this->dateFormats[$format])) {
-      $this->dateFormats[$format] = $this->dateFormatStorage->load($format);
+  /**
+   * Loads the given format pattern for the given langcode.
+   *
+   * @param string $format
+   *   The machine name of the date format.
+   * @param string $langcode
+   *   The langcode of the language to use.
+   *
+   * @return string
+   *   The pattern for the date format in the given language.
+   */
+  protected function dateFormat($format, $langcode) {
+    if (!isset($this->dateFormats[$format][$langcode])) {
+      // Enter a language specific context so the right date format is loaded.
+      $language_context = config_context_enter('Drupal\Core\Config\Context\LanguageConfigContext');
+      $language_context->setLanguage(new Language(array('id' => $langcode)));
+
+      $this->dateFormats[$format][$langcode] = $this->dateFormatStorage->load($format);
+      config_context_leave();
     }
-    return $this->dateFormats[$format];
+    return $this->dateFormats[$format][$langcode];
   }
 
   /**
diff --git a/core/modules/config/lib/Drupal/config/Tests/ConfigLocaleOverride.php b/core/modules/config/lib/Drupal/config/Tests/ConfigLocaleOverride.php
index f3f3ea6ff4314984a0aedfae35e901627689764c..24edb76443d1589ecce2a05a8e5e8ecd7d9b252e 100644
--- a/core/modules/config/lib/Drupal/config/Tests/ConfigLocaleOverride.php
+++ b/core/modules/config/lib/Drupal/config/Tests/ConfigLocaleOverride.php
@@ -170,7 +170,7 @@ function testConfigLocaleLanguageOverride() {
     )));
 
     $language = language_load('fr');
-    $language_config_context = config_context_enter('Drupal\language\LanguageConfigContext');
+    $language_config_context = config_context_enter('Drupal\Core\Config\Context\LanguageConfigContext');
     $language_config_context->setLanguage($language);
     $config = \Drupal::config('config_test.system');
     $this->assertIdentical($config->get('foo'), 'fr bar');
@@ -196,7 +196,7 @@ function testConfigLocaleLanguageOverride() {
     // Enter an english context on top of the german context.
     $language = language_load('en');
     // Create a new language config context to stack on top of the existing one.
-    $en_language_config_context = config_context_enter('Drupal\language\LanguageConfigContext');
+    $en_language_config_context = config_context_enter('Drupal\Core\Config\Context\LanguageConfigContext');
     $en_language_config_context->setLanguage($language);
     $config = \Drupal::config('config_test.system');
     $this->assertIdentical($config->get('foo'), 'en bar');
diff --git a/core/modules/locale/lib/Drupal/locale/Tests/LocaleConfigTranslationTest.php b/core/modules/locale/lib/Drupal/locale/Tests/LocaleConfigTranslationTest.php
index 72998261ea0416101166ae322557fe22d9e430be..3c219ec0dc39706138473ca5f83cba5ad1094dbe 100644
--- a/core/modules/locale/lib/Drupal/locale/Tests/LocaleConfigTranslationTest.php
+++ b/core/modules/locale/lib/Drupal/locale/Tests/LocaleConfigTranslationTest.php
@@ -89,6 +89,37 @@ function testConfigTranslation() {
     $this->drupalGet($langcode);
     $this->assertText($site_name, 'The translated site name is displayed after translations refreshed.');
 
+    // Check default medium date format exists and create a translation for it.
+    $string = $this->storage->findString(array('source' => 'D, m/d/Y - H:i', 'context' => '', 'type' => 'configuration'));
+    $this->assertTrue($string, 'Configuration date formats have been created upon installation.');
+
+    // Translate using the UI so configuration is refreshed.
+    $search = array(
+      'string' => $string->source,
+      'langcode' => $langcode,
+      'translation' => 'all',
+    );
+    $this->drupalPostForm('admin/config/regional/translate', $search, t('Filter'));
+    $textareas = $this->xpath('//textarea');
+    $textarea = current($textareas);
+    $lid = (string) $textarea[0]['name'];
+    $edit = array(
+      $lid => 'D',
+    );
+    $this->drupalPostForm('admin/config/regional/translate', $edit, t('Save translations'));
+
+    $wrapper = $this->container->get('locale.config.typed')->get('system.date_format.medium');
+
+    // Get translation and check we've only got the site name.
+    $translation = $wrapper->getTranslation($langcode);
+    $format = $translation->get('pattern')->get('php')->getValue();
+    $this->assertEqual($format, 'D', 'Got the right date format pattern after translation.');
+
+    // Formatting the date 8 / 27 / 1985 @ 13:37 EST with pattern D should
+    // display "Tue".
+    $formatted_date = format_date(494015820, $type = 'medium', NULL, NULL, $langcode);
+    $this->assertEqual($formatted_date, 'Tue', 'Got the right formatted date using the date format translation pattern.');
+
     // Assert strings from image module config are not available.
     $string = $this->storage->findString(array('source' => 'Medium (220x220)', 'context' => '', 'type' => 'configuration'));
     $this->assertFalse($string, 'Configuration strings have been created upon installation.');
diff --git a/core/modules/system/config/schema/system.data_types.schema.yml b/core/modules/system/config/schema/system.data_types.schema.yml
index 7c5a420c9e8c68445f2d07aead86ca5f587525d1..ab375b6ebae14a3c1e245b2c565de8361de8d2f8 100644
--- a/core/modules/system/config/schema/system.data_types.schema.yml
+++ b/core/modules/system/config/schema/system.data_types.schema.yml
@@ -53,6 +53,12 @@ text:
   label: 'Text'
   translatable: true
 
+# PHP Date format string that is translatable.
+date_format:
+  type: string
+  label: 'PHP date format'
+  translatable: true
+
 # Complex extended data types:
 
 # Mail text with subject and body parts.
diff --git a/core/modules/system/config/schema/system.schema.yml b/core/modules/system/config/schema/system.schema.yml
index 82fcec695248de06ed488d3080e2da593ff3c43f..020e9d300505482813952189ab9e769d7cdccd0c 100644
--- a/core/modules/system/config/schema/system.schema.yml
+++ b/core/modules/system/config/schema/system.schema.yml
@@ -141,7 +141,7 @@ system.date_format.*:
       label: 'Format string'
       mapping:
         php:
-          type: string
+          type: date_format
           label: 'PHP date format'
         intl:
           type: string