So, once the human race had discovered roughly this number of words (give or take a few for whatever language existed at the time, and minus the useless words demanded by grammar) then humans had a Turing Complete language? That must have been a crucial point for the evolution of human culture.
Much more crucial than the Turing completeness of the grammer was certainly the ability to write language down, which conserved knowledge and language for multiple generations as long as the decoding skills were passed along.
What effect this really had can be observed with the introduction of mechanical printing presses which reduced spatial and temporal distances of information flow significantly.
The internet might yet be another of those things..
