I’m sitting in the sun on one of the first mild days of the spring, talking with a modern-day flintknapper about the origins of human language. His name is Neill Bovaird, and he’s neither an archaeologist nor a linguist, just a 38-year-old bearded guy with a smartphone in his pocket who uses Stone Age technology to produce Stone Age tools. Bovaird has been flintknapping for a couple decades, and as we talk, the gok gok gok of him striking a smaller rock against a larger one punctuates our conversation. Every now and then the gokking stops: A new flake, sharper than a razor blade, breaks off in his palm.

I’ve come to see Bovaird, who teaches wilderness-survival skills in western Massachusetts, because I want to better understand the latest theories on the emergence of language—particularly a new body of research arguing that