I am testing this theme at http://d-theme.com/alchemist. The following html element, in page.tpl.php, is missing the language and direction attributes.
<html xmlns="http://www.w3.org/1999/xhtml">

For a test I expanded the html element to:
<html xmlns="http://www.w3.org/1999/xhtml" lang="<?php print $language->language; ?>" xml:lang="<?php print $language->language; ?>" dir="<?php print $language->dir; ?>">