- 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
- Another well-known person who supports the critical period hypothesis would be Noam Chomsky.