An often asked question in the Sites forum is "How do I add translated pages to my site". It is not really necessary to do this with Google Sites because the Google Translate element has been added to Sites. Now, visitors to your Google Site with a different language setting than your site can hit the translate button to translate the whole site to the language of their choice.

Users will see a Translate link at the bottom-right of the site:
 translate link

Or a bar like this at the top:

If you still want to add links to translated versions of your site, you can do so.
  1. Copy the URL of your Google Site home page.
  2. Then go to, select the language you want to translate to, paste in your URL and hit translate.  
  3. Then copy that "translated URL".  
  4. Then go back to your Google Site, edit the page, add a link and paste the URL you copied from the Google translate page.