How does one load a language file for a 3rd party Joomla extension?

OK, it's as simple as replacing JPATH_SITE with the full path to the module like so:

$language = JFactory::getLanguage();
$language->load('mod_foo', JPATH_SITE.'/modules/mod_foo');

This of course assumes that the language file you want to load is located at:

/modules/mod_foo/language/xx-XX/xx-XX.mod_foo.ini

I had tried this before posting the question, but it didn't work due to a silly typo.