Make your own free website on
Home | Nativist Theory | Non-Nativist Theory | Theorists | Language | The Genie Case | References
Critical Period Theory

Language Development


  • The Critical Period Hypothesis states that the first few years of life is the most crucial time for an individual to acquire a first language if presented with adequate stimuli.
  • If language input does not occur until after this time, the individual will never achieve a full command of language.
  • An example of this would be The Genie Case.

  • Unfortunately, due to the many differences in children, evidence for such a time period is limited, and support mainly comes from the theoretical arguments and analogies to other critical periods in biology such as visual development, but nonetheless, the critical period for language developement is widely accepted.
  • However, the nature of this phenomenon has been one of the most fiercely debated issues in pyscholinguistics and cognitive science in general for decades.
  • The first people to introduce the critical period of language development were Wilder Penfield (a Montreal neurologist) and co-author Lamar Roberts in their publication Speech and Brain Mechanisms in 1959.
  • The critical period was further explored in 1967 in Eric Lenneburg's book Biological Foundations of Language 
  • Lenneberg proposed that brain lateralisation (the longitudinal fissure that separates the brain into two distinct cerebral hemispheres) at puberty is the mechanism which closes down the brain's ability to acquire language.
  • Another well-known person who supports the critical period hypothesis would be Noam Chomsky.