diff --git a/core/includes/bootstrap.inc b/core/includes/bootstrap.inc
index e64bfca..0681f56 100644
--- a/core/includes/bootstrap.inc
+++ b/core/includes/bootstrap.inc
@@ -1426,7 +1426,7 @@ function drupal_unpack($obj, $field = 'data') {
  * available to code that needs localization. See st() and get_t() for
  * alternatives.
  *
- * @param $string
+ * @param $input
  *   A string containing the English string to translate.
  * @param $args
  *   An associative array of replacements to make after translation. Based
@@ -1447,13 +1447,24 @@ function drupal_unpack($obj, $field = 'data') {
  * @see format_string()
  * @ingroup sanitization
  */
-function t($string, array $args = array(), array $options = array()) {
+function t($input, array $args = array(), array $options = array()) {
   static $custom_strings;
 
   // Merge in default.
   if (empty($options['langcode'])) {
     $options['langcode'] = drupal_container()->get(LANGUAGE_TYPE_INTERFACE)->langcode;
   }
+  if (is_array($input)) {
+    if (isset($input[$options['langcode']])) {
+      return $input[$options['langcode']];
+    }
+    elseif (isset($input['_default'])) {
+      return $input[$input['_default']];
+    }
+    else {
+      return $input['en'];
+    }
+  }
   if (empty($options['context'])) {
     $options['context'] = '';
   }
@@ -1466,18 +1477,18 @@ function t($string, array $args = array(), array $options = array()) {
     $custom_strings[$options['langcode']] = variable_get('locale_custom_strings_' . $options['langcode'], array());
   }
   // Custom strings work for English too, even if locale module is disabled.
-  if (isset($custom_strings[$options['langcode']][$options['context']][$string])) {
-    $string = $custom_strings[$options['langcode']][$options['context']][$string];
+  if (isset($custom_strings[$options['langcode']][$options['context']][$input])) {
+    $input = $custom_strings[$options['langcode']][$options['context']][$input];
   }
   // Translate with locale module if enabled.
   elseif ($options['langcode'] != LANGUAGE_SYSTEM && ($options['langcode'] != 'en' || variable_get('locale_translate_english', FALSE)) && function_exists('locale')) {
-    $string = locale($string, $options['context'], $options['langcode']);
+    $input = locale($input, $options['context'], $options['langcode']);
   }
   if (empty($args)) {
-    return $string;
+    return $input;
   }
   else {
-    return format_string($string, $args);
+    return format_string($input, $args);
   }
 }
 
diff --git a/core/lib/Drupal/Core/Config/DrupalConfig.php b/core/lib/Drupal/Core/Config/DrupalConfig.php
index f5a9220..9eb90d4 100644
--- a/core/lib/Drupal/Core/Config/DrupalConfig.php
+++ b/core/lib/Drupal/Core/Config/DrupalConfig.php
@@ -132,18 +132,25 @@ class DrupalConfig {
    * @param $value
    *   @todo
    */
-  public function set($key, $value) {
+  public function set($key, $value, $subkey = '') {
     // Type-cast value into a string.
     $value = $this->castValue($value);
 
     // The dot/period is a reserved character; it may appear between keys, but
     // not within keys.
+    $ref = &$this->data;
+    if ($subkey) {
+      if (empty($this->data['_default'])) {
+        $this->data['_default'] = $subkey;
+      }
+      $ref = &$ref[$subkey];
+    }
     $parts = explode('.', $key);
     if (count($parts) == 1) {
-      $this->data[$key] = $value;
+      $ref[$key] = $value;
     }
     else {
-      drupal_array_set_nested_value($this->data, $parts, $value);
+      drupal_array_set_nested_value($ref, $parts, $value);
     }
     return $this;
   }