diff -u b/core/modules/language/language.admin.inc b/core/modules/language/language.admin.inc
--- b/core/modules/language/language.admin.inc
+++ b/core/modules/language/language.admin.inc
@@ -876,9 +876,9 @@
       '#size' => 20,
     ),
     'drupal_langcode' => array(
-      '#type' => 'textfield',
+      '#type' => 'select',
+      '#options' => $language_options,
       '#default_value' => '',
-      '#size' => 20,
     ),
   );
 
@@ -928,7 +928,7 @@
 
   $header = array(
     t('Browser language code'),
-    t('Drupal language code'),
+    t('Drupal language'),
     t('Operations'),
   );
 
@@ -953,13 +953,10 @@
         elseif (preg_match('/[^a-z\-]/', $data['browser_langcode'])) {
           form_set_error('mappings][' . $key . '][browser_langcode', 'Browser language codes can only contain lowercase letters and a hyphen(-).');
         }
-        elseif (preg_match('/[^a-z\-]/', $data['drupal_langcode'])) {
-          form_set_error('mappings][' . $key . '][drupal_langcode', 'Drupal language codes can only contain lowercase letters and a hyphen(-).');
-        }
         $unique_values[$data['browser_langcode']] = $data['drupal_langcode'];
       }
       elseif (empty($data['browser_langcode']) xor empty($data['drupal_langcode'])) {
-        form_set_error('mappings][' . $key . '][drupal_langcode', 'Both browser and Drupal language codes must be provided.');
+        form_set_error('mappings][' . $key . '][drupal_langcode', 'Both browser language code and Drupal language must be provided.');
       }
     }
     else {
@@ -971,18 +968,12 @@
         elseif (preg_match('/[^a-z\-]/', $data['browser_langcode'])) {
           form_set_error('mappings][' . $key . '][browser_langcode', 'Browser language codes can only contain lowercase letters and a hyphen(-).');
         }
-        elseif (preg_match('/[^a-z\-]/', $data['drupal_langcode'])) {
-          form_set_error('mappings][' . $key . '][drupal_langcode', 'Drupal language codes can only contain lowercase letters and a hyphen(-).');
-        }
         $unique_values[$data['browser_langcode']] = $data['drupal_langcode'];
       }
       else {
         if (empty($data['browser_langcode'])) {
           form_set_error('mappings][' . $key . '][browser_langcode', 'Browser language code cannot be blank.');
         }
-        if (empty($data['drupal_langcode'])) {
-          form_set_error('mappings][' . $key . '][drupal_langcode', 'Drupal language code cannot be blank.');
-        }
       }
     }
   }
diff -u b/core/modules/language/language.module b/core/modules/language/language.module
--- b/core/modules/language/language.module
+++ b/core/modules/language/language.module
@@ -38,7 +38,7 @@
       return $output;
 
     case 'admin/config/regional/language/detection/browser':
-      $output = '<p>' . t('Browsers use different language codes to refer to the same languages. You can add and edit mappings from browser language codes to the language codes used by Drupal.') . '</p>';
+      $output = '<p>' . t('Browsers use different language codes to refer to the same languages. You can add and edit mappings from browser language codes to the <a href="@configure-languages">languages used by Drupal</a>.', array('@configure-languages' => url('admin/config/regional/language'))) . '</p>';
       return $output;
 
     case 'admin/structure/block/manage/%/%':
diff -u b/core/modules/language/lib/Drupal/language/Tests/LanguageBrowserDetectionUnitTest.php b/core/modules/language/lib/Drupal/language/Tests/LanguageBrowserDetectionUnitTest.php
--- b/core/modules/language/lib/Drupal/language/Tests/LanguageBrowserDetectionUnitTest.php
+++ b/core/modules/language/lib/Drupal/language/Tests/LanguageBrowserDetectionUnitTest.php
@@ -206,21 +206,13 @@
     $this->drupalPost('admin/config/regional/language/detection/browser', $edit, t('Save configuration'));
     $this->assertText('Browser language codes must be unique.', 'Error message displayed.');
 
-    // Add a new custom mapping with only a browser language code.
-    $edit = array(
-      'mappings[_new][browser_langcode]' => 'xxxx',
-      'mappings[_new][drupal_langcode]' => '',
-    );
-    $this->drupalPost('admin/config/regional/language/detection/browser', $edit, t('Save configuration'));
-    $this->assertText(t('Both browser and Drupal language codes must be provided.'), 'Error message displayed.');
-
     // Add a new custom mapping with only a Drupal language code.
     $edit = array(
       'mappings[_new][browser_langcode]' => '',
       'mappings[_new][drupal_langcode]' => 'en',
     );
     $this->drupalPost('admin/config/regional/language/detection/browser', $edit, t('Save configuration'));
-    $this->assertText(t('Both browser and Drupal language codes must be provided.'), 'Error message displayed.');
+    $this->assertText(t('Both browser language code and Drupal language must be provided.'), 'Error message displayed.');
 
     // Change browser language code of our custom mapping to zh-sg.
     $edit = array(