Coos and babbles: Language learning in ‘pre-verbal’ babies

Evelyne is a lecturer in the department of psychology at Goldsmiths. She studied Speech and Language Therapy, Neuroscience and Psychology. She conducts research on infant neurocognitive development and the role of early communicative experience in shaping this process. She uses various brain imaging methods to investigate how the infant brain develops functional specialisation for social stimuli, such as language, human voices and faces. Evelyne’s most recent work has focused on bilingual infants as well as hearing infants with deaf mothers.

Before they say their first words, babies are often described as ‘pre-verbal’. This may be interpreted as saying that they are too young to have a conversation with an adult. However, language experience is more crucial in infancy than in any other period of life. Here is a short explanation of why that is…

Babies start learning language even before birth. In roughly the last trimester of pregnancy, the foetus’ hearing system becomes functional and they start perceiving the sound and vibrations of their mother’s voice. On the first day after birth, babies prefer to listen to their mother’s voice as opposed to the voice of another woman. They also prefer to listen to the language that their mother was speaking in pregnancy as opposed to a language they have never heard. This suggests that not only foetuses can hear, but that they can also learn in utero. They are indeed learning the basis of voice and language processing using their mother’s voice as a signal.

It takes on average another 12 months before a baby starts producing recognisable words. But we rarely recognise how much work this achievement represents. Before they can say ‘mummy’ for the first time, babies need to understand that the sounds people make have meanings. They also need to perceive the different sounds that are part of the language they are hearing. They need to associate a particular series of sounds (m-u-m-i) with an object (their mother). Finally, they need to learn to place their own tongue, lips and palate in the specific position that allows producing this exact series of sounds (or something close enough to be recognised!).

Babies need to accumulate thousands of hours of language experience in order to achieve these complex tasks. Language that is addressed to the baby has a lot more impact on a baby’s learning than language that is overheard, for example when both parents are speaking to each other. Why is that? When an adult speaks to a baby, they usually change their voice and language to make it more accessible. They tend to use a higher pitch and slower pace, with a lot more intonation and repetition then when they speak to another adult. This type of language, called ‘infant-directed speech’ or ‘motherese’, is used spontaneously by adults around the world to teach language by emphasising the important words and their boundaries.

There is another key element that makes language addressed to the baby so crucial: communication. When a parent engages in a ‘mini conversation’ with their baby, they often look at each other, imitate intonation and gestures and take turn in contributing to the exchange. A great example of this kind of communication went viral on social media last year ( Babies LOVE this type of interaction with their family and it prompts them to pay attention to the language they are hearing and to learn the first few rules of human communication.

Language experience is crucially important in infancy because the brain is in the process of developing a neural system to process it. In a brain imaging study with young babies, we found that the infant brain responds to non-speech vocalisations like cries and laughter in a very similar way as the adult brain ( However, language is a lot more complex and development of a brain system to process it takes longer. It is while listening to language (or seeing sign language such as British Sign Language) that the baby’s brain progressively develops areas that are specialised for processing languages. However, if a child grows up without full access to a language, their brain organises in a way that does not involve a fully developed language system. Because the brain is less plastic after infancy, language learning is then a lot more difficult and limited. This happens for example in some cases where a child’s deafness is not detected early enough, or intervention is not established to make a language accessible to the child. Having missed on language experience in what we call the ‘sensitive period’ of brain development, these children can struggle to fully learn any language later on.

The type of language experience a baby receives also has an impact on their brain organisation for language. Some babies are exposed to a single language, while others are exposed to two or more languages. Some babies are exposed to a signed language, if they or their parents are deaf. In a recent study, we found that by four months of age, these differences in language experience already impact on brain activation for language ( For example, we found that babies exposed to more than 1 language activated the right hemisphere of the brain to a greater extent in response to language.

However, regardless of the number of languages, or the modality of the languages (spoken or signed languages) that a baby is exposed to, it is absolutely clear that more instances of successful communication between a baby and their family leads to better language learning. In turn, enhanced language skills give a young child the best chances of successful socialisation and learning in school. For this reason, it is never too early to start chatting with babies. Responding to their cooing and babbling is not only fun, but also an important part of a parent’s role!