When managing a multilingual WordPress blog, and having posts in several languages, it might happen that some posts that have been translated are not linked between each other, with PolyLang plugin.
See below example, this published Polish version of a post is not linked to any other language.
In the posts list, it is clearly visible that the Polish and Spanish versions of this post are not linked, as the option to create a post in these languages is available.
Select one of the posts, and go to edit it
There, on the right side, in the languages section, start looking for the localized version of the post with a few keywords, and select the right version
Do it for every language in which the post has already been translated
And don’t forget to press the update button in the publish section
In the all posts menu, it is now visible that the translations are linked to the other languages
And when displaying the post, the language choice is now available