As reported by BBC, it is easier for people to absorb new knowledge before the age of 17-18, after which this ability declines. The results of this study, published in the journal Cognition, were obtained after analyzing an English grammar test taken by 670,000 people of different ages and nationalities. To reach a wider audience, the test was published on the social network Facebook.
Participants, in particular, were asked to check whether a sentence in English was grammatically correct. After completing the test, participants had to indicate their age, the period of learning English, and the circumstances under which they began to study it.
Approximately 246,000 of those who took the exam grew up in an English-speaking environment and spoke only English as children, while for all others English was not their native language. The most common first languages (other than English) were Finnish, Turkish, German, Russian, and Hungarian.
Most of the participants were young people aged 20-30. The youngest were about 10 years old, and the oldest were nearly 80.
The researchers analyzed the data using a computer program and concluded that the ability to memorize grammar is best developed in childhood, declines somewhat in adolescence, and weakens in adulthood.
The idea that it is easiest to learn another language in childhood is not new. But those who take up language learning at an older age can master it well without reaching the level of a native speaker, the researchers claim.
It is not entirely clear what causes the decline in language learning ability by age 18. Scientists attribute this to the brain's ability to adapt and change in adulthood.
Josh Tenenbaum, one of the study's authors from the Massachusetts Institute of Technology, said: "There may be biological changes. It may be related to cultural and social aspects. In many cultures, the period of childhood and adolescence lasts until about 17-18 years. After that, you leave home, maybe start working or enter university. All these factors affect the ability to learn another language."
But this does not mean that it is useless for adults to learn a new language. According to scientists, learning another language has a positive effect on the brain and may even help slow the development of dementia.
Marilyn Vihman, a faculty member in the Department of Language and Linguistic Science at the University of York, said: "The claim that it is impossible to achieve a native level when learning another language if you do not start in childhood is not indisputable. Although such cases are rare, they do occur, and there is documentary evidence. There are cases where 20-year-olds learn a language so well that they could pass for spies. There are two, three, or four such cases. I don't think there is a critical age threshold, only a period that begins after adolescence. This happens to many, but not to all."
Another University of York faculty member, Daniela Trenkic, noted that the study only considered grammatical aspects of language. "You can be an excellent conversationalist even if your speech does not reach the level of a native speaker and your sentence grammar is not perfect."