“Thanks ETL, but this looks like more “why were Neandertals speechless” crap.”
Is that an accepted fact because I would be really interested in how they determined that?
It's hard to prove a negative here since speech doesn't fossilize, but a similar question might be "Why were Neanderthals less capable of technological and cultural innovation than humans" - they used the same crude stone tools for their entire 400 thousand year history (except what they got from exchanges with humans towards the end of their history), while we kept on innovating. We were smart and versatile enough to change our mode of life when the climate, plants, and animals changed all around us at the end of the Ice Age, they weren't and couldn't compete. Now we have evidence from skulls and genes to help explain why.
Not anymore it's not. It was a a priori bias against Neandertal ancestry, part of the endemic racism of the academic community.