Werker – critical period for language acquisition

The question of whether there’s a critical period for language development, I think is one of the most interesting questions in language acquisition. And if someone had asked me this question five years ago, I would have answered very confidently Yes, that there is a critical period for language acquisition. And there is indeed a lot of evidence that is consistent with the notion of a critical period. And this comes from children who are hard of hearing and are not exposed to any patterned language input until they have the opportunity to see a sign language. And this is the work of Elissa Newport and Rachel Mayberry and others that have shown that children who are exposed to a sign language before the age of seven have a much better chance of fully developing a language than do children who are not. And there’s similar work from children’s ability to acquire a second language. There the “critical” period looks a little bit later, maybe to age 11.  

On the other hand, more recent data suggests that even the sort of sacred notion of a critical period for language acquisition needs to be qualified. That there may be a critical period for acquisition of the first language. You may need to have some kind of patterned input in the first several years of life in order to be able to acquire a language but the idea of a critical period for a second language acquisition may be a little bit more plastic than we once supposed. That if we change the exposure conditions and the training conditions, there may be more adaptability and capacity to acquire a second language, later, than we once thought.