In terms of learning a second language, the standard has always been that the younger a person is when attempting a new language, the better they will be at it. It’s called the “Critical Period Hypothesis” first proposed by Canadian neurologists Wilder Penfield and Lamar Roberts in 1959 and then further asserted by Eric Lenneberg in 1967. Since then, research attempting to validate or disprove the hypothesis has been prolific in the field of neuroscience.
What is known is that the brain is develops at a rapid pace during childhood. Neuroscientists cite the plasticity of the brain---its ability to gain more knowledge memory and skills---as the reason for some of the ease young children have with a second language. During the period right after a child is born, called the “exuberant” period” in child development, neural circuits are being formed at a faster pace than any other time. New synaptic connections are being created to carry the electrical signals involved in development across the brain.
Lenneberg put this critical period between the ages of 2-13. It’s during this time period that children have the brain biology to support new skills and knowledge, they have the desire to learn and in general they are immersed in language at home and provided with education once they reach school. It’s a period ripe with opportunity, but is it actually critical? Some studies say no, and that it’s more of a “sensitive” period in that it’s more advantageous, but that language development doesn’t just completely stop at age 13.
One of these was a study in Germany at the University of Groningen, in collaboration with the University of Essex, in which investigators looked at brain waves obtained by EEGs to understand how the brain processes a new language. They looked at whether there was a sudden drop in the ability to learn a language at a certain age or if the ability to learn declines gradually over a longer period time, but still continues into adulthood and middle age.
In this study, it turned out that grammar was a key part of the equation. If the grammar in the native language is significantly different than the new language being learned, then it is harder as a person grows older. The EEG results were also analyzed in a method that is more accurate than simple repeated averaging, which can result in a loss of detail that could impact the results. They used generalized additive modeling, a statistical technique that allows all of the rich data that EEGs collect to be figured into the outcome. This study showed there is no support for a critical period of language opportunity. The ability to learn gets less as we age, but it doesn’t stop abruptly at the beginning of the teen years.
There’s also a difference between learning a language, which requires specific lessons and a purposeful effort as opposed to language acquisition, which happens passively as a result of being exposed to language over time. In short, it’s never too late to try to learn another language. The brain might take longer to incorporate new sounds and new grammar, but it’s worth the time. The video below explains more about language and how we learn it.
Sources: University of Groningen
, PLOS One
, The Telegraph