Baby talk helps babies’ brains process speech in their first year of life
Marina Kalashnikova – m.kalashnikova@bcbl.eu.au
Basque Center on Cognition, Brain and Language
Paseo Mikeletegi 69,
San Sebastian, Spain, 20009
Popular version of paper 2aSCa
Presented Tuesday morning, May 14, 2019
177th ASA Meeting, Louisville, KY
When adults interact with young babies, they use a special type of speech that is slow, melodic, warm, and happy. This speech type or register is known as baby talk or infant-directed speech. Babies like infant-directed speech, and they usually reward adults for using it by paying attention, smiling, and vocalising in response. Thus, the use of infant-directed speech allows parents to convey warm and positive emotions to their babies to make them feel safe, comfort and soothe them. Our research demonstrates that the benefits of infant-directed speech go even further, and that in fact, it may be a powerful tool that adults have at their disposal to assist their young babies in the process of learning language.
When infants come to this world, they have the general capacity to learn any language, but in their first year of life, they must use the speech input from their environment to fine-tune this ability and become language-specific listeners and learners. Any adult who has ever heard someone speaking a foreign language can imagine how difficult this task is since unfamiliar speech usually sounds like one continuous string with no clues about where individual words start and end, and what sounds are used to make up words. This is similar to infants’ first experiences with language, but they have access to infant-directed speech, which assists them in two ways. First, its attention-grabbing properties help infants focus on the speech directed to them over all the other speech and non-speech sounds that they hear in their surroundings. Second, infant-directed speech is characterised by exaggerated speech sounds (i.e., clearer distinctions between different vowel sounds like ee, oo, and ah), which are easier for infants to perceive, discriminate, learn, and later reproduce.
This evidence comes from a series of experiments in which we recorded brain activity in infants from 4 to 9 months of age when they listened to speech passages or to isolated vowel sounds produced in infant-directed or in adult-directed speech. Our results showed that when infants heard infant-directed speech, their brain responses were more mature and similar to the responses of adult brains in response to speech. This indicates that the early encoding of infant-directed speech is less effortful and more efficient.
This efficiency in encoding the speech signal leads to better segmentation of speech into meaningful units, formation of speech sound categories, and comprehension of speech. Thus adults, perhaps unconsciously, provide their young babies with just the type of speech input that they need to succeed in the challenging tasks of learning language.