At one time there was a couple of Joomla extensions that would intercept all outbound Joomla emails (or those components you select) and it would allow you to replace the email with your own 'beautiful' version. I believed these supported multi-lange as well. That said, I am not sure how you would know which language to choose unless each user defined their language preference.
Perhaps acymailing can do this for you as well? When you add a new moodle user to a acymailing list, send that user an email from acymailing which I believe can have different language version. For this however Antonio would need to comment if the Joomdle to Acymailing plugins allow you to pass the course_url as a Acymailing Tag.
