The American linguist Philip Lieberman, who has played a central role in the research on the Neanderthal vocal tract, writes in his 1998 book Eve spoke. Human language and human evolution (p. 8):
Neanderthals clearly possessed language and speech, but their speech capabilities were intermediate between those of still earlier hominids and those of modern humans. Neanderthal speech would immediately have been perceived as being different from that of our [modern human] ancestors.
Let us conclude this discussion with the conjecture that language may have developed gradually, and that Neanderthals had some kind of language, but that their language did not reach the stage of development of the language that came into existence in modern humans approximately 130 000–40 000 years ago.