What did they talk about? An article in Current Biology says that Neanderthal possessed the FOXP-2 gene which biologists indicate is the 'speech' gene.
As they did not reach extinction in Europe until 33,000 to 24,000 years ago, it means that these people could have been musing around the cave fires, chatting about the stars, sun, moon, and even their own mortality 100,000 years ago.
The article says, "The finding, say the researchers, “establishes that these changes [in FOXP2 that distinguish it from the chimp version and, thus, presumably help confer the capacity for speech and language] were present in the common ancestor of modern humans and Neanderthals.” Our lineage might have been a much chattier past than anyone suspected."
The artwork of Neanderthal in the caves of southern France indicate that these people interacted with their environment and, apparently, wanted to communicate what was important to them in the paintings. Their brains were sufficiently large to think, make tools, hunt, make weapons, jewelry, and to paint.
Did they ever think about spirituality? Did they make offerings to a god? Did they talk to each other about an after life?
It would be another 30,000 years before Adam and Eve began strolling in the garden on cool evenings talking with God, according to Genesis. Why did God wait so long, a mere 4000 years ago, before showing himself to his people? Did he not like Neanderthals? That reconstructed likeness of a Neanderthal boy makes him look like a European. These people were not freaks of nature.
Why did God only first speak to the Jews? I can't figure that out. I feel sorry for the hundreds of generations of Neanderthal who never knew of God. All of those wasted lives.