Chimpanzee Even chimpanzees cannot learn to speak. © Thomas Lersch.

By Royal Society University Research Fellow Dr. Simon E. Fisher
Wellcome Trust Centre for Human Genetics University of Oxford

What is human language?

A coding system that allows us to convey thoughts and ideas from one person to another, through speech, sign or the written word. It is extraordinarily powerful, because it takes a finite set of symbols and uses rules to combine them into a potentially infinite number of expressions, not only describing the present, but also past, future and even abstract concepts.

How do we learn it?

To acquire fluent spoken language, infants need to become experts in the rapid co-ordinated movements of jaw, lips, tongue and palate used to generate speech, as well as masters in decoding incoming streams of sound. They must acquire vocabularies comprising thousands of words and discover how to assemble these into novel meaningful utterances. So long as they hear other people speaking around them, most young children achieve such remarkable feats almost effortlessly, without any formal teaching at all.

Why don't animals talk?

There are many communication systems in the natural world, but none match the proficiency and complexity of human language. Chimpanzees, our closest living relatives, cannot learn to speak, even given intensive training. It is thought that answers to this enigma may be buried in the human genome; that unique aspects of our genetic make-up help us build brains that are ready to acquire language.

How do we know which genes are relevant?

One way of tracking them down is to analyse chromosomes from families with inherited difficulties in speech and language development. The first gene to be discovered using this method goes by the name of FOXP2. Curiously, while many animals have their own versions of the gene, FOXP2 seems to have changed in interesting ways during human evolution.