ABSTRACT
I propose a model for the evolution of human language that takes into account evidence derived by means of the comparative method introduced by Charles Darwin. We can only study the physical characteristics and behavior of living species. Stories based on conjecture, although entertaining, concerning the presumed life-styles of extinct hominids or our ancestors 150,000 years ago are no substitute. Therefore, studies of the physiology, brains, and behavior of chimpanzees, other animals, and human beings provide the only relevant database. We can conclude that human linguistic ability appears to involve quantitative increases in primitive capacities evident in living nonhuman primates and other species, plus “derived” features that must have evolved since the divergence of hominids from an ancestral species common to both apes and human beings. Evolutionary biologists use the term primitive feature to designate an attribute that can be traced back to the common ancestor of many related species. The five fingers of the human hand can be traced back in evolutionary time to the common ancestors of present day frogs and human beings. Derived features, such as a horse';s hoof, are those that differentiate particular species.
