An ELT Glossary : The Critical Period Hypothesis

  • Definition : This hypothesis suggests that there is a period in childhood when language acquisition can take place effortlessly and naturally, but that after adolescence the brain is no longer able to process language in this way. 

  • Example : A child who goes to live in a foreign country will "pick up" a language just by being exposed to it, whereas an adult may need formal instruction

  •  The hypothesis is associated with the work of Lenneberg in the 1960s. It is criticised by researchers into second language Acquisition such as Krashen who contend that acquisition remains possible throughout life, and that difficulties encountered by adults come from other sources such as affective factors.