Up until the 1990s, many parents in the United States avoided exposing their children to other languages. They claimed this would confuse kids and stunt their linguistic development. Previously, researchers endorsed what was known as “double semi-lingualism,” the xenophobic belief that children will not become fully proficient in either language if another is introduced before they master their native language. This stance advocates waiting to provide formal education in another language until adolescence. Not coincidentally, this is when courses in other languages are already taught in American schools.
However, recent research has shown that this insular perspective is not supported. In fact, the evidence shows the opposite. In many cases, people can never become truly bilingual if they begin learning another language after the age of 10. That does not mean adult learners should despair—they are still equipped to become proficient in other languages. Rather, this newer research suggests that children are very capable of learning two or more languages at the same time. Further, the second language should be introduced as early as possible to give the best odds of bilingualism.
The Difference between Fluency and Bilingualism
There is a crucial distinction between being bilingual and being fluent in another language. People who are fluent in another language will still make minor, predictable grammatical errors and require refreshers on key points after time has gone by, particularly if they haven’t spoken the language in a while. They are also likely to make errors surrounding puns or other subtleties of language.
Someone who is bilingual speaks with native ease in both languages and does not make typical, non-native grammatical or usage errors. The person can easily switch between the two languages without needing to translate between them. While people can become fluent in languages they start learning later in life, bilingualism requires early exposure and instruction.
A Basic Overview of Childhood Neuroplasticity
Our understanding of child brain development has changed and improved a great deal over time. We now have a limited understanding of why a toddler can hear two languages with different grammars and distinguish easily between them. To put it simply, a child’s brain works differently from an adult’s. In the first month of life, the infant’s brain is developing as many as 3 billion new synaptic connections per second. Everything around the newborn gets absorbed deeply into the brain.
During months 1 to 6, the brain is focusing on the sounds it hears in everyday life and learning how to reproduce them physically. At this age, a baby’s mouth can make all the sounds used in human language. Because we only reproduce the sounds that we hear, our mouths and palates will be shaped by the sounds that we actually make. This means we usually will lose the ability to make certain sounds that are necessary for native fluency in another language.
By about 8 months of age, a baby’s brain has around 1,000 trillion synaptic connections. From this point on, that number starts to decrease. The connections being used are strengthened and the ones not being used atrophy. In the average human, about half of these connections persist at age 10, which is the stable state. Up to this point, the brain easily absorbs vocabulary and creates new architecture for grammar. By about age 12, the foundations for language are set and this scaffolding is complete. Learning a new language after this point is definitely possible, but it will not be embedded in the brain as deeply and thoroughly as a native language.
At younger ages, children are absorbing information in a different way because they are still creating language frameworks. Small children are sponges for language, absorbing it effortlessly rather than through structured grammar and vocabulary lessons. In adolescence, at around age 12, it is still possible for children to make rapid progress in formal language instruction, particularly in comparison to small children. This is likely why researchers previously recommended commencing formal education in other languages at this age. Researchers had yet to develop a more complete understanding of childhood neuroplasticity.
The Bottom Line about When to Teach Another Language
Today, the recommendation for parents who want their children to be bilingual is to introduce the second language as early as possible and to expose the child to both languages simultaneously. The answer to the question of when to start learning still has some points that need to be clarified. Some researchers now argue that the window closes earlier than age 12—it is likely closer to age 6 or 7. While it will take a long time to develop a more nuanced understanding, experts essentially agree that getting the earliest start possible results in the best outcomes.