In reading these pieces, I was struck by how great our popular misconceptions of evolution (as both a biological and sociological phenomenon) really are. By “our” here I of course am referring to those of us who know enough about science to believe in evolution, but who are not so specialized as to really grasp the particulars, as the authors are.
One such misconception is that evolution is inherently positive, linear, and moving in an “upward” direction. According to this framing, evolution is a spectrum ranging from “less evolved” to “more evolved” along which you can plot different species and compare them competitively against each other. In this conception, humans are “more evolved” than other animal species because we’ve developed the cognitive abilities that allows us to create complex languages, networks, societies, and so forth. But this is a completely misguided view of evolution. Evolution is not the directional moving along a continuum, but more of a “spreading out.”
Bringing this back to language, as Deacon notes in “The Symbolic Species,” there is a false belief that language is just the natural result of evolution, something all species will get to eventually if only they “evolve enough.” It is merely the complexity of our notion of language that is preventing other species from adopting it. If this were the case, however, then surely there would exist among at least some species a “simple” language (beyond the nonverbal communication exhibited by some species along with humans) at a “lower” level of complexity along the evolutionary scale. But this does not exist, and it’s nearly impossible even to teach the most simplistic of our language forms to some of the most “intelligent” nonhuman species. 
Because evolution is a “spreading out,” different species ended up in vastly different places—even on different paradigms, one might say. Nonhuman species ended up on paradigms in which they do not have language in the same way we do, even if they may have developed other forms of communication or other methods of adaptation. Humans ended up on a paradigm in which we have the ability to learn language, and this in turn allowed us the ability to develop other cognitive functions, which built on each other to give us the human tools (“tools” not in the artefact sense) we have today.
One final, unrelated thought I’ll end on: I do wonder how our current world population explosion will affect the evolution of our cognitive abilities. Our improved agricultural knowledge and practices (which have allowed us to produce more than enough food) combined with falling mortality rates (as a result of a reduction in conflict deaths and infectious diseases, as well as improved medical technology) have led to an unprecedented growth in population. As Wong claims in “The Morning of the Modern Mind,” increased population size is the situation most likely to cause “advanced” cultural attributes. With more competition for resources, humans were forced to develop innovative technologies and methods in order to survive.  What kind of effects will our current population boom have on the technologies we develop, and how will these affect our cognitive abilities more generally?
 Deacon, Terrence William. The Symbolic Species: The Co-evolution of Language and the Brain. New York: W.W. Norton, 1998. Print.
 Wong, Kate. “The Morning of the Modern Mind.” Scientific American 292.6 (2005): 86-95. Web.