What can forest guenons “tell” us about the origin of language?

Human language is by far the most elaborated communication system, but talking, like any behaviour, has not left any clear physical signs of its evolution. Although plausible but quantitatively limited explanations can be drawn from archaeological studies, we will probably never find real direct evidence of the evolutionary path of language. Consequently, the phylogenetic origin of language is still currently debated intensively. A number of recent theoretical and empirical advances show that the evolution of language is a tractable problem when approached at an interdisciplinary level (Hauser et al. 2002, Oller & Griebel 2008). One way to solve this problem is to compare the anatomy, the communicative mechanisms and the cognitive capacities of humans and other more or less phylogenetically-related animals. The question addressed is then ‘Can we find the roots of the complex human language in animal vocal communication?’