Hello,
As I've posted on another forum thread - You can define unsubscribe URL within the
newsletter template in following format instead of original macro:
<a href="http://YourDomain.com/SpecialPages/Unsubscribe.aspx?subscriberguid={%SubscriberGUID%}&newsletterguid={%NewsletterGUID%}&issueid={%IssueID%}">Unsubscribe</a>
You need to paste that code using Source mode. Please note that you need to set correct unsubscribe page which will suit your situation. Moreover you could create another language version of unsubscribe page to receive appropriate unsubscribe confirmation message.
This way you can generate the unsubscribe link in any language.
Best Regards
Ondrej Vasil