IF YOU found yourself in a cocktail bar with a Neanderthal man, what would he say? A good conversation is one of the great joys of being human, but it is not clear just how far back in the hominid lineage the ability to use language stretches. The question of when grunts and yelps turned into words and phrases is a tricky one. One way of trying to answer it is to look in the fossil record for evidence about what modern humanity's closest relatives could do.

Svante Pääbo, of the Max Planck Institute for Evolutionary Anthropology in Leipzig, and his colleagues have done just that. Dr Pääbo is an expert in extracting and interpreting the DNA of fossils. As he reports in the latest issue of Current Biology, he and his team have worked their magic on a gene called FOXP2 found in Neanderthal remains from northern Spain.

The reason for picking this particular gene is that it is the only one known so far to have a direct connection with speech. In 1990, a family with an inherited speech disorder known as verbal dyspraxia drew the attention of genetics researchers. Those researchers identified a mutation in FOXP2 as the cause of the dyspraxia.

Since then FOXP2 has been the subject of intensive study. It has been linked to the production of birdsong and the ultrasonic musings of mice. It is a conservative type, not changing much from species to species. But it has undergone two changes since humans split from chimpanzees 6m years ago, and some researchers believe these changes played a crucial role in the development of speech and language.

If these changes are common to modern humans and Neanderthals, they must predate the separation of the line leading to Homo sapiens from the one leading to Homo neanderthalensis. Dr Pääbo's research suggests precisely that: the FOXP2 genes from modern humans and Neanderthals are essentially the same. To the extent that the gene enables language, it enables (or enabled) it in both species.

There has been much speculation about Neanderthals' ability to speak. They were endowed with a hyoid bone, which anchors the tongue and allows a wide variety of movements of the larynx. Neanderthal skulls also show evidence of a large hypoglossal canal. This is the route taken by the nerves that supply the tongue. As such, it is a requisite for the exquisitely complex movements of speech. Moreover, the inner-ear structure of Homo heidelbergensis, an ancestor of Neanderthals, shows that this species was highly sensitive to the frequencies of sound that are associated with speech.

That Neanderthals also shared with moderns the single known genetic component of speech is another clue that they possessed the necessary apparatus for having a good natter. But suggestive as that is, the question remains open. FOXP2 is almost certainly not “the language gene”. Without doubt, it is involved in the control and regulation of the motions of speech, but whether it plays a role in the cognitive processes that must precede talking remains unclear—jokes about engaging brain before putting mouth in gear notwithstanding.

The idea that the forebears of modern humans could talk would scupper the notion that language was the force that created modern human culture—otherwise, why would they not have built civilisations? But it would make that chat with a Neanderthal much more interesting.