This reminded me of the French movie "la guerre de feu" about the people who found fire in the cave period. The interesting part of the movie was not in French. It's not in English either. There are no words in the movie. You should watch it.
There are actually two distinct languages (a kind of Proto-Proto-Proto-Indo-European and Proto-Proto-Proto-Uralic) spoken in the movie, created by Anthony Burgess. He later wrote an essay (the title of which escapes me ATM) about the thinking behind it.
Some background: https://www.anthonyburgess.org/quest-for-fire/about-quest-fo...
https://archive.is/20240311220449/https://www.nytimes.com/19...
I find it amusing that we can reconstruct that PIE speakers had a verb for "to get high", but we can't reconstruct their noun for "bear", because it was taboo: speaking of the bear was like speaking of the devil, and so all we know are all the different ways the different languages chose to talk about the bear without saying its name.
the movie you speak of is the first on the list: Quest for Fire (1981)