What I'd wonder about is the relationship between language use and tool use.
Makeshift hammer hits toe, ancient man yells "Owww". Everyone around him knew what he meant. He points at hammer, says "Gru", and his toe "uf", and voila, everyone that was around him now has a vocabulary of 3 words :-) Then it expands with pointing....
Language is a meta-technology, a technology that facilitates transmission of other technologies, as well as itself. I suspect that language had its origins at the same time as humanity's tool use transitioned from serendipitous accident to learned technology. From there language and humanity's technological both rapidly evolved together in a self-reinforcing complementary positive feedback spiral.