According to the researchers’ calculations, Neanderthals could most likely have heard voiceless consonants made without the vocal cords. These included voiceless stops such as “t” and “k” and voiceless frictions such as “f”, “s” and “th”. Voiceless consonants cannot be broadcast aloud in a landscape – try shouting “ththth” or “sssss” – which could suggest that these consonants were used for communication between members of the same species nearby.

Although Neanderthals had the correct anatomy to support human language, the authors concede that Neanderthals’ physical abilities imply neither mental abilities nor the knowledge necessary for human language.

“Language is not required for language,” said Robert Berwick, a computational linguist at the Massachusetts Institute of Technology who was not involved in the study. Dr. Berwick was not convinced of the authors’ interpretation of what the reconstructed ear indicates about Neanderthal communication; In his view, the Neanderthals’ consonant-friendly sweet spot does not imply the ability to learn human language. “If we were to develop with differently shaped ears, we would simply use the contrasts that we can still perceive differently,” he said.

The Neanderthal language issue may never be fully resolved even if evidence continues to accumulate. “There are no more Neanderthals to speak of,” said Dr. Goldfield.

Numerous recent discoveries about the nature of Neanderthal life suggest that they behaved symbolically, wore jewelry, made cave art and buried their dead. These revelations helped liberate Neanderthals from the longstanding perception that early humans were primitive beasts, a myth partly rooted in racist ideology.

For a long time, scientists tended to believe that there was a “leap” that separated modern humans from the rest of the biological world such as cognition and language, according to Dr. Dediu. “But Neanderthals were probably just as human as we are, just in a different way,” he said.

The most striking evidence of the inwardness of the Neanderthals lies in the back of the Bruniquel Cave in France, where archaeologists found two concentric rings of broken stalagmites, traces of fire and burned bones. The stalagmites had been broken off 176,500 years ago – a time when Neanderthals were the only people in the region.