Guide to raising bilingual kids

Theory of brain development and language acquisition

Still uncertain about why you should start your baby’s second language education from birth? Why not wait until the age of 4, so he/she can learn how to speak one language correctly and then add another? For this purpose I want to explain underlying processes in baby’s brain and timeline of its development.

A neuron

So the basic unit of any brain is a neuron – a nerve cell that has numerous connections to other neurons. The connections are called synapses. At birth, baby’s brain already has about all of the neurons it will ever have. Even more importantly, synapses are formed at a faster rate during the first three years than at any other time. In fact, the brain creates many more of them than it needs: at the age of two, the brain has up to twice as many synapses as it will have in adulthood. These surplus connections are gradually eliminated throughout childhood and adolescence. You can see it on the picture below:

The synapses and their map can be called knowledge. Every time we learn something the new connections are established. The more we learn (from language to gross motor activities), the better and more efficient those connections are. But don’t be confused, the more doesn’t mean the better. There is a reason those surplus connections are trimmed – the aim is efficiency, and too many connections are a burden. As if you built a city and every neighborhood would have too many roads with crossroads and traffic lights every 10 metres.

A child’s senses report to the brain about her environment and experiences, and this input stimulates neural activity. Speech sounds, for example, stimulate activity in language-related brain regions. If the amount of input increases (if more speech is heard) synapses between neurons in that area will be activated more often. This repeated use strengthens a synapse. Synapses that are rarely used remain weak and are more likely to be eliminated. Synapse strength contributes to the connectivity and efficiency of the networks that support learning, memory, and other cognitive abilities. Therefore, a child’s experiences not only determine what information enters the brain, but also influence how the brain processes information for the rest of her life.

The outstanding abilities of newborn babies demonstrate the extent of prenatal brain development. Newborns can recognize human faces, which they prefer over other objects, and can even discriminate between happy and sad expressions. At birth, a baby knows mother’s voice and may be able to recognize the sounds of stories his/her mother read in the 3rd trimester.

At about three months, infants’ power of recognition improves dramatically. For the first few months, a baby in an English-speaking home can distinguish between the sounds of a foreign language. The ability is lost by the end of her first year: the language heard at home wired the brain for English. I have already mentioned it in the section “Advantages” clause 4. After this period, all the other languages learned later will function differently in the brain and achieving accent-free speech becomes a very hard task.

The second year’s most dramatic changes involve the brain’s language areas, which are developing more synapses and becoming more interconnected. These changes lead to a spike in language abilities and vocabulary volume. Often a child’s vocabulary will quadruple between his first and second birthday.

Synaptic density in the prefrontal cortex probably reaches its peak during the third year, up to 200 percent of its adult level. This region also continues to create and strengthen networks with other areas. As a result, complex cognitive abilities are being improved and consolidated. At this stage, for example, children are better able to use the past to interpret present events. They also have more cognitive flexibility and a better understanding of cause and effect.

Early brain development is the foundation of human adaptability and resilience, but these qualities come at a price. Because experiences have such a great potential to affect brain development, children are especially vulnerable to persistent negative influences during this period. On the other hand, these early years are a window of opportunity for parents, caregivers, and communities: positive early experiences have a huge effect on children’s chances to achieve success and happiness.

That is why exposing your kid to a second language since birth is not a burden for your baby, but a favor, saving him/her thousands of hours, spent struggling through boring grammar books and exercises.

And that is it with the theory, next article is Preparation