The most important stage of language learning

A large amount of evidence shows that it is more difficult for adults to learn a new foreign language than children to learn the language. Therefore, scientists have proposed that there is a “critical period” for language learning. However, the length of this period and its root cause are still unknown.

A new study conducted by the Massachusetts Institute of Technology shows that children can better learn foreign language grammar for much longer than we expected, and this stage can last until the age of 17 or 18. The study also found that it is almost impossible for people to have the same level of mastery of a foreign language as a native speaker, unless they start learning the language before the age of 10.

“If you want to have knowledge of English grammar at the native level, you should start at about 10 years old. We did not observe a significant difference between people who started learning English at birth and those who started learning English at the age of 10. We began to observe a trend of decline in the level of learning among people who started learning after the age of 18,” said Joshua Hartshorne, assistant professor of psychology at Boston College, who conducted this research at MIT as a postdoc.

Researchers have found that people who learn languages ​​between the ages of 10 and 18 can still learn faster, but because the window period before their learning ability declines is shortened, they cannot reach the proficiency of native speakers. The survey results are based on the analysis of grammar tests conducted on nearly 670,000 people, which is the largest database constructed by people to study language learning ability so far.

Josh Tenenbaum, professor of brain and cognitive sciences at MIT and author of the paper, said: “Until now, it is still very difficult to collect all the data on how long the critical period lasts.” This is a rare opportunity in the field of science, despite many cleverness. People have already thought about and discussed this issue, we can still study this seemingly old problem and take a new perspective to see what others may not have understood. “

Steven Pinker, a professor of psychology at Harvard University, is also one of the authors of the paper, which was published in the journal Cognition on May 1.

Image: Statista

Fast learner

Although it is a typical phenomenon that children learn languages ​​more easily than adults, and this phenomenon often occurs in immigrant families, this trend is difficult to study in a laboratory environment. Researchers take adults and children to the laboratory and teach them some new language elements. After testing them, they will find that adults do indeed learn better under these conditions. Hartshorne said that such research may not accurately replicate the long-term learning process.

He said: “Whatever the reason, we rarely see in our daily lives that adults can fully master a language. This situation has existed for a long time.”

It is difficult and time-consuming to spend many years tracking people who learn a language, so researchers have proposed a different approach. They decided to record thousands of people at different stages of English learning. By measuring the grammatical abilities of many people of different ages and starting to learn English at different stages, they can obtain enough data to draw some meaningful conclusions. .

Hartshorne’s original estimate was that they would need at least 500,000 participants-a scale unprecedented in this type of research. The challenge he faced was the need to attract so many subjects, so he needed to design a grammar test that was interesting enough to spread quickly.

With the help of some MIT undergraduates, Hartshorne searched some literature on language learning to find the grammatical rules most likely to hinder non-native speakers. He cited some problems that can expose these grammatical errors, such as judging whether sentences such as Yesterday John wanted to won the race are grammatically correct.

In order to attract more people to participate in the test, he also included questions that are not very relevant to language learning, but can show which English dialects the subjects can accept. For example, an English speaker from Canada may think that a sentence like “I’m done dinner” is correct, while others will not.

A few hours after the test was posted on Facebook, the 10-minute “Which English?” test has gone viral.

“The next few weeks will be used to maintain the operation of the website, because we get a lot of traffic,” Hartshorne said. “From this point I learned that the design of this experiment is fun enough.”

Long critical period

After taking the test, users need to fill in their current age and the age at which they started learning English, as well as other information about the language background. The researchers finally obtained complete data of 669,498 people. After they have a lot of data, they must figure out how to analyze the data.

“We have to figure out how many years these people have learned when they start using this language, and how they are exposed to foreign languages: did they learn in the classroom or did they immigrate to an English-speaking country?” Hartshorne said.

Researchers have developed and tested various calculation models to understand which ones are most consistent with their results. They found that the best interpretation of the data is that people are still strong in grammar learning until the age of 17 or 18, after which time their learning ability will decline. The results of the study show that the critical period for language learning is much longer than previously thought by cognitive scientists.

“It surprised us,” Hartshorne said. “The previous controversy was whether learning ability began to decline after birth, at the age of 5, or from adolescence.”

The author points out that adults can still learn foreign languages ​​well, but they cannot reach the level of native speakers if they start learning as a teenager or adult.

It is not clear what caused the critical period to end at around 18 years of age. Researchers believe that cultural factors may play a role, but changes in brain plasticity may also occur at that age.

“It may be a biological change. It may also be a social or cultural factor,” Tenenbaum said. “In many societies, people have a minor stage before about 17 or 18. After that, people will leave home, maybe work full-time or become a college student. These may affect the speed of language learning.”

Hartshorne now plans to conduct some related research in the laboratory at Boston College, which includes comparing native speakers and non-native speakers among Spanish speakers. He also plans to study whether various aspects of grammar have different critical periods, and whether accents have shorter critical periods.

The researchers also hope that other scientists can use the data they publish on the Internet to conduct more research.

Hartshorne said: “There are many other content in these data that can be analyzed. We really hope to attract the attention of other scientists, because the relevant data has been collected and can be used.”

The research was funded by the National Institutes of Health and the Center for Psychology, Brain, and Machines at the Massachusetts Institute of Technology.