I don't know what plugin are you talking about, but if you want to add some video content in different language, you must change the movie/tv translation first:

A/ If the record is already translated to the desired language, you can change it here

B/ If the record isn't translated to the desired language yet, you can add the missing translation record by entering edit section and then adding (or changing) "language=" parameter of the URL in your web browser:

https://www.themoviedb.org/movie/475557-joker/edit?active_nav_item=primary_facts
https://www.themoviedb.org/movie/475557-joker/edit?active_nav_item=primary_facts&language=pl

and then confirm that you want to add new translation to the movie/tv.

It sounds like this might be a specific request about the integration of TMDb and a third party plugin. If that's the case @vibovsky, I suggest contacting the developer of that plugin. We are not able to provide support for third party apps and plugins.