The riddle of speech

The development of speech and languages has fascinated linguists, philosophers and biologists down the ages, given the enormous role they have played in social and cultural evolution of humans. This led to a proliferation of ideas and hypotheses, but with no conclusive evidence to back any of them, partly because language has not evolved in any nonhuman primates or other animals as parallels for study and partly because there is no associated fossil and archaeological evidence [1]. Another key factor is that virtually no genes associated with linguistic processes have yet been discovered [1].

Once molecular biologists entered the fray, the FOXP2 gene attracted huge interest as a crucial candidate for the evolution of speech…

Once molecular biologists entered the fray, the FOXP2 gene attracted huge interest as a crucial candidate for the evolution of speech and it has dominated research for almost two decades. That is changing now as other candidate genes emerge as major players in the development of vocalization. It also led to greater understanding of the distinction between the vocalization of speech, which involves motor coordination of the larynx, and the emergence of complex language including grammar. Indeed, unravelling the genes involved in vocalization is a necessary precursor to developing a rigorous genetic basis for the evolution of speech and ultimately language, which involves even closer integration with neurological functions.

Unlike language, vocalization is shared with other species, notably songbirds, bats, dolphins and whales. This makes it easier to identify shared genes that either emerged in common ancestors or in parallel. There is also scope for studying the impact of deleterious mutations associated with speech both in humans and in transgenic mouse models—although those animals are not capable of learned vocalization, some of these genes affect general acquisition …