When you translate your site and add sub domains, this changes the sub domain for every static link also.
For SEO purposes, some static links need to retain their original domain. For example, a link back to the English version of your site should not change to fr.yoursite.com when someone is browsing the French version.
To ensure your static links on translated versions of your site keep the correct sub domain, enter the below code in front of the static link:
Added in front of your link, it would look like the below: