Many Second Language Acquisition authors believe that the earlier a child begins to learn a foreign language, the easier they acquire that language. Some talk of there being a 'window of opportunity' for learning a new language. Of course this analogy suggests that there might be a time when it is too early to learn, but also too late to learn a foreign language.
Professor John Hattie of the University of Melbourne who does extensive research on how little babies learn, recommends that parents help their children to learn language by using gestures in much the same way that we do in our ‘Sam and Mel’ video English lessons. However, it is evident that a young infant has neither the cognitive development nor the motor skills that would enable it to read and write at that stage. So it is important to keep a measured approach as to what foreign language skills a child might learn at a young age.
Is there a moment when the window shuts and it is too late to learn a foreign language? Several years ago I spoke to Steven Pinker, MIT professor of Brain and Cognitive Sciences, and author of The Language Instinct. His research has shown that when children reach the age of puberty, a very small section of the brain actually reduces in size and disappears. This part of the brain is known to be linked to language acquisition. The suggestion was that it took more cognitive effort to learn a foreign language after puberty, whereas a younger child might more naturally absorb the new language like a sponge.
It might require greater cognitive effort to learn a new language as one gets older, but an adolescent or adult has greater cognitive capacity than a child to do so. At that stage there are other factors that play a significant role: How motivated is an adolescent to learn a foreign language, and how much time are they prepared to dedicate to it? At age 14 I had no interest in learning French and consequently failed miserably at the task. At 25 I was very motivated to learn French and became a fluent speaker (albeit with a noticeable English accent). It is for this reason that the 'Sam and Mel' method puts the emphasis on learner motivation. Furthermore, a motivated learner will spend the time necessary to acquire the new language.
So when is the best time to learn a foreign language? At the time when the learner is motivated to do so. If language learning is fun and rewarding, then a child will enjoy their lessons. If it is boring then they will quickly lose focus. Adults, on the other hand, are motivated by other factors such as the intellectual challenge, the attraction to a foreign culture or the desire to travel or live in a foreign country.