Language and the human brain

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Language and the human brain

• Linguistics 101

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The human brain

• Composed of /- 10 billion nerve cells (neurons).
• The highest level of the brain is the cerebral
  cortex (found only in mammals, and human has the
  greatest proportion of cortex).
• Language representation and processing resides in
  the cortex.

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Modularity of the brain

• The brain is divided into distinct anatomical
  faculties that are directly responsible for
  specific cognitive functions.
• Left hemisphere is superior for language,
  rhythmic perception, temporal-order judgments,
  and mathematical thinking skills
• Right hemisphere does better in pattern-matching
  tasks, recognizing faces, and spatial orientation.

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Language in the brain

• Evidence for language lateralization
• Paul Broca (French) in 1864
• found that damage to the front
• part of the left hemisphere
• resulted in loss of speech.

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Language in the brain

• Brocas aphasia1
• intelligence not necessarily affected
• understanding not necessarily affected
• production severely impaired
• Labored speech
• Frequent pauses
• Trouble with function words
• 1aphasia any language disorder resulting from
  brain damage

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Language in the brain

• Karl Wernicke (German) in 1874.
• Wernickes aphasia
• Fluent speech
• Good intonation
• Lexical errors
• Nonsense words
• Word salad
• Comprehension impaired

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Language in the brain

• Brocas area
• controls
• Syntax
• Wernickes area controls
• Semantics

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Language in the brain

• Is language totally left-lateralized?
• Not completely.
• Adults with left cerebral hemispheres surgically
  removed lose most, but not all of their
  linguistic competence.
• They lose the ability to speak and process
  complex syntactic patterns, but retain some
  language comprehension ability.

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Language autonomy

• Is language faculty already present from the
  time of birth or is it derived from more general
  intelligence?
• Children with SLI (Specific Language
  Impairment)
• - No brain lesions.
• - No other cognitive deficits, not autistic or
  retarded, no perceptual problems.
• But, they have difficulties in acquiring
  language.
• ? Language ability ¹ General Cognition

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Language autonomy

• Evidence from aphasia, SLI, and the asymmetry of
  abilities in linguistic savants strongly supports
  the view that language faculty is an autonomous,
  genetically determined, brain module...
• instead of derived from more general
  intelligence.