[Django]-How to set language for django-pagination?

This should happen automatically.
Check your django settings if USE_I18N is set to True and if your LANGUAGE_CODE is set to pl.

For further information take a look at the django localization page. You can find a more detailed documentation of how the translation in django works here.

There’s also a list of language codes, I guess pl should be correct.

You can either change the language setting of your browser, which will send the appropriate headers with each request and trigger the translation to be used, or you can provide a language setting selection so the user can choose their language.

You can roll your own code to provide this interface or use django-user-accounts.

You also might want to check that you have the appropriate middleware installed as described in this documenation.