A critical period for second language acquisition: Evidence from 2/3 million English speakers

Dr. Joshua Hartshorne, Principle Investigator at Boston College’s Language Learning Lab, along with Joshua B. Tenenbaum, and Steven Pinker just had an article accepted in Cognition! Their main finding is that reaching native-level fluency in a second language is “nearly impossible” if one begins to learn the second language after age 10. But this critical period is not necessarily attributed to a decrease in language skills at age 10 and beyond. A possible explanation can be that entering the workforce or college decreases our free time to practice language skills, but the current data cannot determine whether this is a case of environmental or biological factors. Dr. Hartshorne continues to find new and exciting ways to collect data from large amount of possible subjects. Dr. Hartshorne and colleagues created a quiz called “Which English?” and it collected data from 669,498 native and non-native English speakers. This 10-minute quiz was shared on Facebook more than 300,000 times and was on the front page of Reddit. The trending quiz attracted so many people with the hook that it would guess the quiz-takers’ native language, dialect, and home country based on their answers to the quiz. At the end of the quiz, the participants gave their true native language. Through the answers that were given, Dr. Hartshorne and his co-authors were able to infer how grammar-learning ability changes with age. The methodology that was used paves the way for future research and spurs more research on this specific topic and on language learning as a whole.

Check out popular news articles from TIME and MIT News that discuss Dr. Hartshorne’s paper. You can also listen to an interview between BBC and Dr. Hartshorne here.