Linguistic prerequisites in the primate lineage

Language is perhaps the single most important feature that distinguishes humans from the rest of the living world. Human language is an openended system of communication in which syntactic rules encode information of great complexity, and it is therefore of particular interest how this capacity has evolved. Theories of language origins are all faced with one problem: how to explain the evolution of a highly complex and sophisticated cognitive capacity in an extremely short period of time. Humans probably did not have the anatomical and neural prerequisites to produce the full range of modern speech until very recently (Lieberman 2000: 136). A recent comparative genetic analysis has provided additional empirical support, showing that non-human primates differ genetically from modern humans in a region on chromosome 7, which codes for the FOXP2 protein (Enard et al. 2002). Other work has shown that the FOXP2 gene is crucially involved in the development of normal speech abilities in humans (Fisher et al. 1998). The genetic differences in this region distinguishing us from our closest living relatives are the result of a few mutations, which have not become stabilized in the human population until very recently, about 200,000 years ago. Overall, this has led to the hypothesis that the human-specific form of the FOXP2 protein is essentially involved in brain development, affecting the ability to fine-control orofacial movements and thus the capacity to develop proficient speech (Enard et al. 2002). Yet a time period of 200,000 years, which equals about 7,000 generations, could be too short to evolve the entire necessary cognitive apparatus underlying the language capacity.