Language link

Hi!

I have identical sites in Swedish ans Spanish (https://www.swed.info and https://www.sv.swed.info).
I would like to offer my readers the chance to switch from one language to the other by simple clicking on a link. Not linked just to the static home page of the other language but to the page/ post they are at.
Could you suggest a plugin that can deliver that?
All plugins I found change the language of wordpress or translate the content. I just want to link to identical parallel WP instalations.
Thanks!