Each page on the JAR website is available in an original language as well as a set of translations (if available). The language of a page is expressed in its URL:

https://jar-online.net/en/issues/32 links to the page in English, https://jar-online.net/es/issues/32 links to the page in Spanish etc.

However, which language version a page is displayed in depends on the 'preferred language' chosen at the top of the site. This choice is not encoded in the URL.

If 'not set' is chosen, the site will redirect the URL to a page's original language.

If a language is chosen, the site will redirect to to that language of a page if it exists; if it does not exist, the site will redirect to a page's original language.

If I want to send a link to a specific language version of a page making sure that I will be shown in that language regardless the 'preferred language' setting, I have to send this URL https://jar-online.net/pt/issues/32?force_language=1 where force language makes sure for a page to be loaded in the language specified.