diff --git a/core/modules/locale/config/schema/locale.schema.yml b/core/modules/locale/config/schema/locale.schema.yml
index 72b89e1..e2d1633 100644
--- a/core/modules/locale/config/schema/locale.schema.yml
+++ b/core/modules/locale/config/schema/locale.schema.yml
@@ -4,6 +4,12 @@ locale.settings:
   type: mapping
   label: 'Translate interface settings'
   mapping:
+    fallback:
+      type: sequence
+      label: 'Fallback language mappings'
+      sequence:
+        - type: string
+          label: 'Language code'
     cache_strings:
       type: boolean
       label: 'Cache strings'
diff --git a/core/modules/locale/locale.module b/core/modules/locale/locale.module
index c880370..4f67fb7 100644
--- a/core/modules/locale/locale.module
+++ b/core/modules/locale/locale.module
@@ -1404,3 +1404,12 @@ function locale_translation_language_table($form_element) {
   }
   return $form_element;
 }
+
+/**
+ * Implements hook_language_fallback_candidates_OPERATION_alter().
+ */
+function locale_language_fallback_candidates_locale_lookup_alter(array &$candidates, array $context) {
+  // @todo (in this patch), return proper fallback for this language based on
+  // settings.
+  $candidates = array();
+}
diff --git a/core/modules/locale/src/Form/LocaleSettingsForm.php b/core/modules/locale/src/Form/LocaleSettingsForm.php
index 0157d5e..b1f2070 100644
--- a/core/modules/locale/src/Form/LocaleSettingsForm.php
+++ b/core/modules/locale/src/Form/LocaleSettingsForm.php
@@ -8,6 +8,7 @@
 
 use Drupal\Core\Form\ConfigFormBase;
 use Drupal\Core\Form\FormStateInterface;
+use Drupal\Core\Language\LanguageInterface;
 
 /**
  * Configure locale settings for this site.
@@ -27,7 +28,40 @@ public function getFormId() {
   public function buildForm(array $form, FormStateInterface $form_state) {
     $config = $this->config('locale.settings');
 
-    $form['update_interval_days'] = array(
+    $languages = \Drupal::languageManager()->getLanguages();
+    if (!empty($languages)) {
+      $form['fallback'] = array(
+        '#title' => $this->t('Interface fallbacks'),
+        '#type' => 'details',
+        '#open' => TRUE,
+        '#tree' => TRUE,
+      );
+
+      foreach ($languages as $language) {
+        // Only add options for languages that are different from the current.
+        $options = array();
+        foreach ($languages as $option_language) {
+          if ($language->getId() != $option_language->getId()) {
+            $options[$option_language->getId()] = $option_language->name;
+          }
+        }
+        $form['fallback'][$language->getId()] = array(
+          '#title' => $this->t('Fall back from %language to', array('%language' => $language->name)),
+          '#type' => 'language_select',
+          '#options' => $options,
+          '#default_value' => $config->get('fallback.' . $language->getId()),
+          '#empty_option' => t('-None-'),
+          '#empty_value' => '',
+        );
+      }
+    }
+
+    $form['updates'] = array(
+      '#type' => 'details',
+      '#open' => TRUE,
+      '#title' => $this->t('Translation updates'),
+    );
+    $form['updates']['update_interval_days'] = array(
       '#type' => 'radios',
       '#title' => t('Check for updates'),
       '#default_value' => $config->get('translation.update_interval_days'),
@@ -46,7 +80,7 @@ public function buildForm(array $form, FormStateInterface $form_state) {
       $description = t('Translation files will not be stored locally. Change the Interface translation directory on the <a href="@url">File system configuration</a> page.', array('@url' => url('admin/config/media/file-system')));
     }
     $form['#translation_directory'] = $directory;
-    $form['use_source'] = array(
+    $form['updates']['use_source'] = array(
       '#type' => 'radios',
       '#title' => t('Translation source'),
       '#default_value' => $config->get('translation.use_source'),
@@ -66,7 +100,7 @@ public function buildForm(array $form, FormStateInterface $form_state) {
     else {
       $default = LOCALE_TRANSLATION_OVERWRITE_NON_CUSTOMIZED;
     }
-    $form['overwrite'] = array(
+    $form['updates']['overwrite'] = array(
       '#type' => 'radios',
       '#title' => t('Import behavior'),
       '#default_value' => $default,
@@ -99,6 +133,8 @@ public function submitForm(array &$form, FormStateInterface $form_state) {
     $values = $form_state->getValues();
 
     $config = $this->config('locale.settings');
+    $config->set('fallback', array_filter($values['fallback']));
+
     $config->set('translation.update_interval_days', $values['update_interval_days'])->save();
     $config->set('translation.use_source', $values['use_source'])->save();