First language acquisition: how do babies learn to differentiate between sounds?
Prof. Paula Fikkert, Professor in Dutch language and culture
A specific line of CLS research on first language acquisition focuses on sound contrasts. How do babies learn the difference between taan and paan? And at what age are they capable of distinguishing a cat from a hat? Professor Paula Fikkert, “The general claim is that children are universal listeners until they are about six months old. This means infants should be capable of differentiating between all sounds used in the world’s languages. After six months, they start fine-tuning to the sound contrasts of their own language and become less sensitive to contrasts in other languages.” In their second year, when children actively start learning words, a remarkable change takes place: they become less sensitive to some, but not all sound contrasts of their own language. For example, Dutch children experience no processing difficulties if the word deur (‘door’) is pronounced as beur (not a real word), but they do experience difficulties if poes (‘cat’) is pronounced as toes (not a real word). Fikkert, “We thought that this was related to the process in which children form lexical representations of words in what we call their mental lexicon: a mental dictionary in which all sorts of information about words is stored.”
The CLS researchers discovered, however, that such asymmetries are also displayed by babies younger than six months. “This is a groundbreaking finding as it goes against the traditional view that babies are universal listeners,” says Fikkert. “Our research shows that when very young, children show biases in their ability to distinguish between sounds. Results like these stress the importance of fine-grained linguistic research on sounds in order to understand first language acquisition.”
Conducting linguistic research with babies is challenging, if only due to their inability to speak. The researchers employ various methods to study babies’ linguistic capabilities. Fikkert, “We use various techniques, such as habituation, where infants watch an object on a screen and simultaneously listen to a series of repetitive sounds, for example: paanpaan paan paan paan. If they start to get bored, they spend less time looking at the screen. At a certain point, when we let them hear a different sound such as taantaan taan taan taan, they once more spend time looking at the screen. Studies within this paradigm provide insights into how sensitive babies are to differences between sounds. In addition to behavioural methods, we also use neuro-imaging techniques.”
In the near future, the researchers aim to unravel how children learn language in interaction with other children. “We already know quite a bit about language acquisition from studying children at home, in interaction with their parents, and in the laboratory. We now aim to deepen this knowledge by looking at spontaneous learning processes,” says Fikkert. To achieve this, the researchers collaborate with a school at which children are able to play language games in a so-called language learning playhouse. Studying the linguistic development of these children will provide insights into what children are linguistically capable of in a natural and social environment.
Fikkert, “How children learn a language is a fascinating process. Any question related to this process is both fundamental and relevant in light of the impact language has on an individual’s life. For example, children that are good at distinguishing the sounds of their native language also seem to be good at learning words. And a rich vocabulary has positive effects on all kinds of aspects later in life. Understanding first language acquisition is therefore of utmost importance.”