If confirmed, the finding could push back the date for the start of the uniquely human skill of spoken language by tens or even hundreds of thousands of years, the scientists say. The researchers were focusing on a small bony channel called the hypoglossal canal that carries nerves from the brain to the tongue. Having larger tongue nerves, the scientists believe, could mean a better ability to form words and sentences. Cartmill said the hypoglossal canal had been overlooked by other scientists seeking for clues to early speech in fossilized jaws, skulls and other parts of the vocal tract. Australopithecus, the earliest humans, had hypoglossal canals that were about one half the size of modern humans.
Apes also have canals about at size.
But Neanderthals, who lived from about 300,000 years ago and disappeared around 27,000 to 30,000 years ago, had hypoglossal canals roughly the same size as people today. Later humans also had large hypoglossal canals. Chatting among Neanderthal and other early humans would push the advent of human speech back beyond 40,000 years ago, when symbols in the archaeological records suggest speech began. The researchers, whose work is published in Tuesday's issue of the Proceedings of the National Academy of Sciences, conducted the study by constructing rubber molds of the bones.