The findings suggest human speech may have originated earlier than some researchers contend. Anthropologists disagree about whether language sprang up rapidly around 50,000 years ago or emerged more gradually over a longer period of time, says Rolf Quam, a paleoanthropologist at the American Natural History Museum in New York and coauthor of the new study.

The auditory bones of 530,000-year-old skulls indicate that an early human species called Homo heidelbergensis may have heard sounds much the way people do today. H. heidelbergensis are thought to be an ancestor of Neandertals. The findings could reignite debate about whether Neandertals could speak, Quam and colleagues report. The study is the first to use a fossil to reconstruct sensory perception in any Homo species, they add.

The skulls are from a site in Atapuerca, Spain called Sima de los Huesos, or “pit of the bones.” The Atapuerca research team, which includes members from many disciplines and universities, used CT scanning of the skulls to reconstruct the size and shape of the ear canals, Quam says.