Stephen Wroe of the University of New South Wales, working with an international team, says the researchers were able to determine how the Hyoid bone -- a horseshoe shaped structure in the neck -- worked in Neanderthals.
Wroe said the findings are "highly suggestive" of complex speech in Neanderthals.
The hyoid bone is crucial for speech, as it supports the root of the tongue. Non-human primates cannot vocalize as humans do because the hyoid bones are not placed in the right position.
The researchers said analysis of a fossil Neanderthal throat bone using 3-D X-ray imaging and mechanical modeling allowed them to see how it worked in relation to other surrounding bones.
"We would argue that this is a very significant step forward," Wroe told the BBC. "It shows that the [analyzed] hyoid doesn't just look like those of modern humans -- it was used in a very similar way."
Many scientists have held that complex language only evolved about 100,000 years ago and only modern humans were capable of vocalizing complex speech.
"Many would argue that our capacity for speech and language is among the most fundamental of characteristics that makes us human," Wroe said. "If Neanderthals also had language then they were truly human too."