Neurolingusitcs- biological & neural
foundation of language
Today’s focus:
Introduction to
English Linguistics
How is language presented and
processed in the human brain?
英語語言學概論
Where is “language”?
BBC003 Wed. 8:10-10:00 (M102)
Week 3
The cerebral cortex:
The brain is composed of the right and left
cerebral hemispheres
The highest level of the brain
(the surface of the brain)
Human brain seen from above
These hemispheres can be
considered to be separate
brain because they show
functional distinctness.
left = analytic tasks
right= overall appreciation
of complex patterns
Contralateral function
Corpus
callosum
(contra=opposite, lateral=side)
The cerebral cortex
Why is it so wrinkled?
Lower brain structures
are shared by almost all
animals.
The human being has
the greatest proportion
of cortex to brain mass
of all animals.
(ex. Reptiles have no
cortex at all)
MRI (magnetic resonance imaging)
The brain is not a uniform mass
(…..means “not unstructured organ”)
Localization
Different human cognitive abilities and
behaviors are localized in specific parts of
the brain.
That different areas of the brain are
responsible for distinct cognitive systems.
It allows a great amount
of cortical matte to be
compressed into the
limited space provided
by the human skull. Up
to 65% of the cortex is
hidden within is holds.
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Question:
Where is the location of “language”?
Broca’s area
“Language is localized to the left
hemisphere of the brain”
(1864)
The study of APHASIA has been the key
What is aphasia?
Evidence:
Language disorder (inability to perceive, process, or
produce language) caused by damage to the brain.
However, it does not affect intelligence.
Broca examined the brain of his patient who
suffered language disorder for over 20 years,
after brain injury. He discovered that the
patient’s brain showed severe damage
(lesion) in the left frontal lobe. (Autopsy study)
Because the patient could not speak, this part
of the brain must be responsible for speech
production.
Wernicke’s area
Paul Broca
1824-1880
Broca’s aphasia
Look at an example on your text book…. (p.39)
“I also found another type of aphasia
which was associated with a lesions
(severe damage) in the more posterior
(rear) position of the left hemisphere.”
Evidence:
Carl Wernicke
1848-1905
Autopsy studies
Not fluent
Great difficulty in producing the needed phonemes to
say a word.
a. “It’s hard to eat with spoon”
b. [… har… i:t….wit….pun] (O’grady et al, 1996: 426)
Functional words / morphemes are missing (agrammatic)
Telegraphic speech (using as few words as possible).
Look at your text book p.39
Production problem?
Broca’s aphasia
Judging the grammaticality of the sentences
1.
2.
3.
4.
The boy ate it up
*The boy ate up it.
*Boy ate it up.
The boy ate up the cake.
Sentence comprehension
1.
2.
3.
The mouse was chased by the cat.
The dog was chased by the cat.
The cat was chased by the mouse.
Syntactic deficit
Wernicke’s aphasia
Look at the examples on your text book (p.40)
Fluent – basically sound very good !
No difficulty producing language: no pause
Basically good syntax: functional words, word order
However…..
Having great difficulty selecting words, organizing
their language production
Their speech rarely makes any sense.
2
Wernicke’s aphasia.
‘it was all in the, what’you call it the,
beffering, you know in the one up the
snocth.’
Jargon aphasia
‘the spleefering are nefererling the
bedayduns in the fenitinring.’
Wernicke’s aphasia :
Patients are generally unaware of their deficit
1.
It is very difficult for a patient to understand the
speech of others.
Misinterpretation and responding in an unexpected way.
2.
‘be daydums de day dums gemansem de
payum’
They also have difficulty naming objects
presented to them as well as in interpreting
words from their mental dictionary (lexicon).
Tendency to produce semantically incoherent speech.
Comprehension deficit
Words are not simply “listed” in our
mental lexicon. (p.41)
Evidence:
So, what does aphasia tell us?
1.
Language is a separate cognitive system
aphasics are cognitively normal (dissociation of
language and cognition)
2.
Within language, separate component can be differently
affected
We find that damage to different parts of the brain
results in different kinds of linguistic impairment (e.g.
syntax, semantics).
Substitution errors by aphasic patients
Neural connection exist among semantically or
phonologically related words.
Agrammatic aphasics:
Content words vs. functional words
They are stored in different components and
Mental grammar is not an undifferentiated system but rather consists
of distinct component with different functions, which interact with
each other.
processed differently.
The language faculty is modular
The Autonomy of Language
More evidence for modularity…
The language faculty is modular. It is
independent from other cognitive systems
with which it interacts.
SLI (specific language impairment)
They suffer from language deficits, but are normal in other regards
Language savants
Individuals with extraordinary language skills, but who are deficient in
general intelligence (e.g. Laura, Christopher) (p.51)
Linguistic ability is not derived from general cognitive ability.
Human is biologically equipped from birth with an
autonomous language faculty (genetic).
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The critical period hypothesis
1.
2.
Language is biologically based
The ability to learn a native language
develops within a fixed period.
Evidence:
The imperfect language learning of persons exposed
to language after this period (e.g. wild child/ adult
second language learners).
Exercises p.64-66
2a./ 2b.
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