Most normatively developing babies begin to speak their first few words by the time they celebrate their first birthday. Most parents, however, talk to their babies long before this time, many using a singsongy cadence of language that researchers refer to as “motherese” and we know that babies can understand and respond to language long before they speak it.
Recent advances in the study of neuroscience have enabled scientists and researchers to learn more about what happens insides babies’ brains before they learn to speak. By studying the brain, neuroscientists have determined that there are critical periods of time when the brain is optimally prepared for particular learning. Although the brain can retain some plasticity after the critical window of opportunity has closed enabling further learning, there are ideal time periods for the development and learning of skills. The critical period of learning to discriminate the sounds of languages is during the first year of life.
Patricia Kuhl is a researcher who presented a TED Talk on language development in babies that is worthwhile for every parent to watch. Kuhl maintains that the only way to preserve a language is to speak it to babies. Kuhl and her colleagues developed a method of testing babies’ ability to discriminate between various sounds spoken in all languages. They discovered that young babies can discriminate between all sounds but that by the time they reach the age of 12 months, they have become culturally bound listeners, meaning that they can only hear the differences between sounds within the language(s) familiar to them.
Kuhl likens the process babies use to discriminate sounds to that of statisticians in that they listen and absorb the data of the sounds they hear spoken to them and absorb the sounds they recognize. Babies learn at an incredible rate, and their learning slows down when the distribution of sounds they hear stabilizes, thus closing the critical window of learning.
Babies who hear English spoken to and around them learn to discriminate the sounds of English while babies who are exposed to Japanese, learn Japanese. Discriminating the sounds leads to later learning to accurately reproduce those sounds through speaking followed by learning to represent the sounds through symbols thus learning to read and write.
Kuhl and her colleagues also found that when babies were exposed to multiple languages, they were able to discriminate the sounds of all the languages, but with one important caveat. The exposure had to be in person; no learning took place if the exposure came through recordings whether audio or video. Babies are social learners who need interaction with other humans in order to learn. According to Kuhl, social interactions turn on the brain and control when the babies take statistics on the sounds they hear.
Kuhl concludes the TED Talk with the promise of exciting implications for the invention of brain based interventions in language learning. Although that prospect is exciting, I have an additional, slightly different take away as I believe that Kuhl’s work highlights the need for parents and caregivers to maximize social interactions with their babies. Parents need to be encouraged to talk to their infants and make the most of the critical learning period for language.
Watch the TED Talk here: