Post #1: Dessalle's book says too many thinkers take language for granted, and he began his remarks by presenting some reasons for thinking seriously about why we have a system that permits the generation of an infinite number of novel remarks. No other animal ever needed such a thing
Post #2 : Dessalles examained the question whether language is a cultural invention that spread like writing or a biological faculty spread through genes and concluded that its origins are biological. In particular, he noted that people have a strong urge to speak and that there are times when it cannot be held back. Language can be understood as a unique biological property.
Post #3: When considering the source of biological properties, evolution, the critical point is"local optimality," the idea that evolution does the best it can, under the circumstances. This idea will prove central to Dessalle's future discussions.
Post #4: An example of reasoning from local optimality is Dessalle's consideration of the sounds of speech. Computers exchange information at very high rates of transmission, and if exchanging information was the function of speech we should expect to operate much more quickly. As it is our slow pace indicates we have not been selected to maximize information exchange. Selection seems to have been favoring some other function.
Post #5 described protolanguage, a pre-syntactic form of speech with a protosemantics that enabled speakers to direct attention to objects without saying anything about them. Protolanguage did allow for one image to follow another. Presumably something like protolanguage served Homo erectus for over a million years.
Post #6 presents the difference between true language and protolanguage. Language has predicates, combining into one sentence a theme that changes or is located and a reference point against which the theme is set.
Post #7 considered the achievement described in the previous post. Dessalles has shown how in a single sentence with true language a speaker can draw attention to both the figure and ground that make the full gestalt of a perception.
Post #8 outlined Dessalles' explanation for why Homo went from protolanguage to full language. It enabled listeners to check speakers for truth and thus enabled people to form coalitions with reliable, informative allies.
Post #9 offered my reason for doubting the explanation given in post 8, although there is no question about the importance of Dessalles' book.