When did humans first develop language? People who study this question are fond of saying "language does not fossilize." That fact makes it difficult to pinpoint when language began. The fossil record can show when hominids first had the necessary anatomy to produce spoken language, but that doesn't mean they were actually using language at that point. Ian Tattersall, paleoanthropologist and curator emeritus at the American Museum of Natural History, told Discover that to determine when language first appeared, researchers must rely on proxies that indicate symbolic thought, which, he said, requires mental abilities identical to those needed for language. "Symbolic thought involves attributing value to symbols, and that's what you're doing in language, too," he explained.
Language May Have Emerged Quite Suddenly
The most common proxies include thumb-sized pieces of ochre engraved with regular geometric shapes, as well as the more celebrated and spectacular cave paintings. These objects were clearly made intentionally, and whoever created them very likely had language. These symbolic objects began to appear around 100,000 years ago. And they emerged, at least in evolutionary terms, quite suddenly. Before about 100,000 years ago, Tattersall explained, Homo sapiens behaved pretty much as their predecessors had. The archaeological record shows no new tools, no documentation of new behaviors. Then, within a few millennia, all sorts of new activities began to take place: body decoration, the production of increasingly intricate symbolic objects, and, perhaps what is the pinnacle of this burst of symbolic activity, stunning cave art. "Within a very short time, certainly in evolutionary terms, there was a complete revolution in behavior, and our behavior became symbolic, and we're involved in doing all kinds of symbolic activities," Tattersall said.
Increased Brain Activity Could Have Led to Language
What spurred that sudden flowering of symbolic thinking? To answer that, researchers looked to genetics. There are 3,000 genes thought to be responsible for cognition in the primate lineage, explained Shigeru Miyagawa, professor emeritus of linguistics at MIT. In a February 2026 paper published in Nature Scientific Reports, Miyagawa and colleagues (including Tattersall) found that about 400,000 years ago, 30 of these genes dramatically — and again quite suddenly — changed the way they coded proteins. "First we saw it in the genes of Homo sapiens, and then we did more investigation and discovered that the same change occurred in Neanderthals and Denisovans," Miyagawa told Discover. This must have happened to our common ancestor, he said, so that puts it back to around 400,000 years ago.
The consequences of those changes dramatically increased not the size of our ancestors' brains, but the number of synapses in the brain. At that point, the brain became capable of forming far more connections among its different parts. "This explosion of synapses led to a huge cognitive evolution," Miyagawa said. Though he added that while we can't say this led to language, this research does suggest that the ability to think symbolically, and by extension use language, may be a by-product of a more efficiently networked brain. Language requires sophisticated and rapid neural processing, and these changes in connectivity may have been what made that possible. "You could never start to have a new behavior like language or symbolic thought if you didn't already have the biology that made it possible," said Tattersall. "Once we had the cognitive evolution with the 30 genes, there was a huge cognitive leap that allowed for the precursor of language to develop in some incremental fashion," Miyagawa added.
Language Can Develop Quickly
It shouldn't be surprising that once the necessary connections were in place in the brain, language developed quickly. We have a modern example of how that happens. Prior to the 1970s, Nicaragua had no sign language. Deaf children were not sent to school and had little to no contact with other deaf people. Then, in the early 1980s, the government opened vocational schools for deaf children, according to a study in Human Development. These schools did not teach sign language. However, that did not stop the kids from communicating. Spending time with other deaf children for the first time in their lives, the students spontaneously invented a fully grammatical sign language, a language that is still used in Nicaragua, according to the Language Acquisition and Development Research Laboratory. "Once they were housed together and had this desire to communicate, pretty quickly they had a sign language, and then it evolved very quickly," said Tattersall.
The question of when language first appeared is not yet settled, but these new studies suggest that it was a relatively recent development, and a relatively rapid one as well.