I found only a tantalizing hint, maahey:
About 40,000 years ago, with the appearance of the Cro-Magnon culture, tool kits started becoming markedly more sophisticated, using a wider variety of raw materials such as bone and antler, and containing new implements for making clothing, engraving and sculpting. Fine artwork, in the form of decorated tools, beads, ivory carvings of humans and animals, clay figurines, musical instruments, and spectacular cave paintings appeared over the next 20,000 years. (Leakey 1994)
Even within the last 100,000 years, the long-term trends towards smaller molars and decreased robustness can be discerned. The face, jaw and teeth of Mesolithic humans (about 10,000 years ago) are about 10% more robust than ours. http://talkorigins.org/faqs/homs/species.htmlIf they made tool kits, they surely talked about them!
The comment about reconstructing the language made me try to find out about skeletal makeup: perhaps we are physiologically different enough from them that we could not make some of the sounds, even if we knew what they were?
