Redirect from "/mynode?language=de" to "/mynode" after storing the language in the cookie Is it possible to remove the "?language=de" query string after Drupal stores the current language in the session and/or the cookie?

I want this so that if someone who speaks French sends a link to someone who speaks German, they will by default send a link that shows in the target user's preferred language.
You want to send them the language code in the url with the link as http://mysite.com/de/my-url-path and then make sure that you've enabled both session and url as detection methods at admin/config/regional/language/configure