Why can we talk when our closest relatives, like Neanderthals, can't?

New research may have uncovered a key piece of the puzzle. It's a small genetic change that exists in modern humans but not in our extinct relatives.

The study focuses on a brain protein called NOVA1, which plays a key role in how nerve cells process information.

Researchers at Rockefeller University in the US have found that a single gene mutation in NOVA1 may have influenced the development of spoken language, setting humans apart from other species early on.

NOVA1 acts as a transmitter in the brain, controlling the expression of other genes in nerve cells.

The human version of the gene differs from the one found in Neanderthals, Denisovans, and other animals by just a small amino acid change. Yet that small difference appears to be the key to unlocking the human voice.

In a test experiment, scientists genetically engineered mice to carry the human version of NOVA1. They developed normally in all other ways, except for their vocalizations.

The pups with the human gene made different calls when separated from their mothers, and the adult males changed their mating calls, producing vocal patterns not previously seen in mice.

These findings suggest that NOVA1 plays an important role in how vocal behavior is formed and processed in the brain, and provide a genetic explanation for why only humans have developed complex speech.

Of course, this is not a complete answer to why human speech is so unique, but it is one of the foundational research findings that contributes to a perfect answer to a unique human ability.