From linguist Daniel Everett at Aeon:
What is the greatest human technological innovation? Fire? The wheel? Penicillin? Clothes? Google? None of these come close. As you read this, you are using the winning technology. The greatest tool in the world is language. Without it there would be no culture, no literature, no science, no history, no commercial enterprise or industry. The genus Homo rules the Earth because it possesses language. But how and when did we build this kingdom of speech? And who is ‘we’? After all, Homo sapiens is just one of several species of humans that have walked the Earth. Does ‘we’ refer to our genus, Homo, or to our species, sapiens?
To discover the answers to these questions, we need to travel back in time at least 1.9 million years ago to the birth of Homo erectus, as they emerged from the ancient process of primate evolution. Erectus had nearly double the brain size of any previous hominin, walked habitually upright, were superb hunters, travelled the world, and sailed to ocean islands. And somewhere along the way they got language. Yes, erectus. Not Neanderthals. Not sapiens. And if erectus invented language, this means that Neanderthals, born more than a million years later, entered a world already linguistic.
Likewise, our species would have emerged into a world that already had language. In spite of the fact that many paleoanthropologists view erectus as little more than a skinny gorilla, of few accomplishments, far too stupid to have language, and lacking a vocal apparatus capable of intelligible speech, the evidence seems overwhelming that they had language.
All that said:
Erectus had relative shortcomings of course, beyond possibly lacking the range of sounds of modern humans. It also lacked the modern form of the important FOXP2 gene that sapiens have. Do the shortcomings of vocal apparatus and primitive genes pose a problem for the idea that erectus had language? Not at all. For example, the evolution of speech was triggered by language – as we developed languages, the modes of expressing them improved over time. Yes, sapiens speech is likely better than erectus speech. But this doesn’t mean that erectus lacked speech. Any mammal could have speech with the sounds they are capable of producing today. They just need the right kind of brain. More.
“Any mammal could have speech with the sounds they are capable of producing today. They just need the right kind of brain”? Talk about an untestable thesis!
But Everett’s main point holds: In theory, the cat could talk. The trouble is, he has nothing to say. That difference is the enduring mystery and Everett is not contributing mere foolishness to the discussion.
Readers may remember Daniel Everett from Tom Wolfe’s book, The Kingdom of Speech, where Wolfe questions claims about the evolution of language by pitting Everett’s research into the Piraha language against the theories of Noam Chomsky.
See also: Linguist Daniel Everett: Homo erectus must have been able to speak, to get to Flores
Modern human remains found in Flores man cave
Kingdom of Speech: But is Everett wrong about Piraha?
and
Tom Wolfe: What we think we know re evolution is wrong
Linguist Noel Rude on Wolfe’s Kingdom of Speech
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Daniel Everett defends himself