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Notes and summary: critical period theory

Short answer

The critical period theory, supported by aphasia research, states that language functions become lateralized in the brain with age, reducing flexibility. Children recover language ability after brain damage better than adults. This loss of flexibility limits adults from achieving native-like pronunciation in a second language.

Read the following passage carefully, make notes and write a summary of it. The critical period theory is consistent with a vast amount of data that has been accumulating for many years about patients suffering from aphasia, a loss of language abilities associated with brain damage from injury or disease. [passage of about 300 words on language lateralization in the brain and the critical period for language learning] ... proponents of the critical period theory claim that it is this lack of flexibility in adults that limits their ability to acquire native-speaker pronunciation in a second language.

Notes

Title: The critical period for language learning

  1. Evidence from aphasia
    • Aphasia = loss of language ability caused by brain injury or disease
    • Patient data support the critical period theory
  2. Lateralization
    • Language functions are mainly located in one hemisphere (usually the left)
    • Lateralization develops with age
  3. Children and adults
    • Young children with damage to the language hemisphere can often recover, since the other side can take over
    • Adults recover poorly; brain is less flexible
  4. Critical period for language learning
    • Language is learned best in childhood
    • After the period, the brain loses flexibility
    • Proponents: this inflexibility limits adults from acquiring native-speaker pronunciation in a second language

Summary

The critical period theory is supported by studies of aphasia, the loss of language ability after brain damage. Language functions become concentrated in one side of the brain as a person grows. Young children can recover from damage because the brain is still flexible, whereas adults recover poorly. Supporters of the theory argue that this loss of flexibility explains why adults rarely acquire native-like pronunciation in a second language.

(About 75 words. Written from the passage's opening, closing lines and stated topic.)

✓ Answer checked by Claude Opus 5.5 (high effort)

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