Translate website without duplicate custom post

I have a website where anyone can post jobs from frontend. The jobs pages are rendered by custom archive and single pages in my custom theme.

I want the website to be multi language with switcher. The problem is to translate the static text in archive-job.php and singe-job.php, without translating the content of jobs.

I tried polylang, but that one needs multiple posts, one for each language. Which means that I need to duplicate the post content

Is there a way to assign multiple languages to same post, without creating redundant posts in polylang (or a free alternative, excepting WPML)?