[The linguistic skills of infants under the age of one year]

It is amazing how all normal children, systematically exposed to a natural language, speak using well-formed sentences by the time they are about 3 years old. This is a universally observed fact that is made possible by a series of mechanisms which mostly remain unexplained. This article reviews a series of studies concerning the linguistic capabilities of infants aged up to twelve months, which were evaluated using both behavioural and neuroimaging methods.

Learning a language means learning its sounds, its words and its grammatical rules. During the first year of life this learning is not very apparent, since it is essentially perceptive and seems to occur without the need to make an effort. Yet, acquiring one's native language is no trivial matter because speech does not offer any known physical evidence that systematically indicates the occurrence of sounds, words and/or grammatical rules. A human being starts to process speech just a few hours after birth; nevertheless, this early sensitivity is not enough to 'know' a particular language. In fact, during their early years, children will have to learn the properties that are relevant to their mother tongue, while at the same time ignoring those that are irrelevant. Processing language is accompanied by changes in brain activity which can be explored using safe neuroimaging methods, such as electroencephalogram recordings and optical topography.

A deeper understanding of the cognitive and neural foundations of the early linguistic skills of children will make a significant contribution to dealing with both normal development and language disorders.