diff --git a/core/themes/bartik/templates/comment.tpl.php b/core/themes/bartik/templates/comment.tpl.php
index 04aa8e5..bd4de97 100644
--- a/core/themes/bartik/templates/comment.tpl.php
+++ b/core/themes/bartik/templates/comment.tpl.php
@@ -71,6 +71,16 @@
       <p class="comment-permalink">
         <?php print $permalink; ?>
       </p>
+      <?php
+        // Indicate the semantic relationship between parent and child comments
+        // for accessibility. The list is difficult to navigate in a screen
+        // reader without this information.
+        if ($parent):
+      ?>
+      <p class="comment-parent element-invisible">
+        <?php print $parent; ?>
+      </p>
+      <?php endif; ?>
     </div>
   </div>