The document discusses language processing in the brain. It describes how psycholinguistics and neurolinguistics study language acquisition, comprehension, and production as they relate to the brain. The left cerebral cortex plays a dominant role in language processing for most right-handed individuals. Dichotic listening tests and split-brain experiments provide evidence of lateralization, with the left hemisphere specialized for language and the right for other functions. Broca's and Wernicke's areas are crucial language centers, with damage resulting in distinct aphasia types characterized by nonfluent or fluent but nonsensical speech, respectively.

1. Language and the Brain
Understanding how language is
represented and processed in the
brain

2. Psycholinguisics
 The study of acquisition, storage,
comprehension and production of
language
 Neurolinguistics: branch of
psycholinguistics dealing with language
and the brain

3. Cerebral cortex
 Cerebral cortex: A one-quarter-inch thick
membrane covering the brain
– consciousness, thinking, learning, emotions,
language
– Constitutes the difference between humans and
other animals
 Corpus callosum: bundle of nerve fibers that
connects the brain’s right and left hemispheres

4. LATERALIZATION
 RIGHT
HEMISPHERE
 holistic reasoning
 music processing
 processing of non-
linguistic sounds
 visual, spatial
processing
 LEFT
HEMISPHERE
 analytic reasoning
 temporal ordering
 arithmetic
 language processing
Each hemisphere specializes in diff. cognitive
functions (referred to as lateralization)

5. Lateralization (Cont’d)
Most right-handers
left-hemisphere dominance for language
Left-handers
generally less lateralized for language
Evidence of Lateralization:
Language damage far more likely following left-hemisphere
damage (70% vs. 1%)
Dichotic listening test
Split-brain patients

6. Dichotic listening test
• Two different stimuli are presented simultaneously
through earphones to the left and right ears
• The listeners are asked to say what they hear
three
two
Which one do you
think is more
accurately reported?

7. Contralateralization
 The connection between
the brain and the body are
almost completely
contralateral
L
sensory
information
R
sensory
information
three
two

8. The right ear advantage (REA)
Brain
BONESANDM
USCLESOFTHEHEAD
three
two
L
L ear
R ear
R
nonlinguistic
sound
processing
language
processing
 Listeners can identify linguistic stimuli more
accurately when presented to their right ear.
two

9. The left ear advantage
Brain
BONESANDM
USCLESOFTHEHEAD
Ha ha ha
Zzzz
L
L ear
R ear
R
Listeners can identify nonlinguistic stimuli more accurately when
presented to their left ear.
Riiing!
nonlinguistic
sound
processing
language
processing

10. Split brain experiments
 The hemispheres of the brain are
connected by the corpus callosum
 Corpus callosum severed to prevent
severe seizures
 In these experiments, patients are
blindfolded and an object (let’s say a
key) is placed in their right or left hand

11. Split-brain patients & language
Brain
R
L
key in
left hand

12. Split-brain patients & language
Brain
R
L
key in
right
hand

13. Split Brain Experiments
 KEY IN RIGHT
HAND
– Patient can name
object
 KEY IN LEFT HAND
– Patient unable to
name object

14. Broca’s area
FRONT
BACK
Angular gyrus
Language centers
Speech production
Syntactic info
Language comprehension
Lexicon
Integrates visual &
auditory info
Crucial for reading
Wernicke’s area

15. Language Disorders
 A damage to one of these areas will
affect the ability to produce/perceive
language
– Aphasia:
– Broca’s Aphasia
– Wernicke’s Aphasia

16. Broca’s area
 Involved in speech production
– motor programming for articulation
 Involved in morphosyntactic analysis
– Inflection
– Structural complexity
 Add grammatical refinements to content words
selected in Wernicke’s area.

17. Sample speech: Broca’s
aphasia
•Examiner: Tell me, what did you do
before you retired?
•Aphasic: Uh, uh, uh, pub, par, partender,
no.
•Examiner: Carpenter?
•Aphasic: (Nodding to signal yes)
Carpenter, tuh, tuh, twenty
year.
(Akmajian et al. 2001: p. 543)

18. Broca’s Aphasia and
Syntactic Disorder
 Broca’s aphasics tend to omit inflectional morphemes
(-ing, -ed, -en, -s)—necessary for syntax
 Broca’s aphasics can’t determine grammaticality in
following sentences:
– The boy ate it up.
– * The boy ate up it.
– * Boy ate it up.
– The boy ate up the cake.

19. Broca’s Aphasia and
Syntactic Disorder
 a. The mouse was chased by the cat.
 b. The cat was chased by the mouse
 Broca’s aphasiacs tend to interpret (a)
correctly, but they tend to give (b) the
same interpretation as (a)
 Our understanding of (a) and (b) is
driven by syntax; a Broca’s aphasiac’s
understanding is driven by semantics.

20. Wernicke’s area
 Essential to language comprehension
 Involved in selection/evaluation of content
words (contained in lexicon)

21. Sample speech: Wernicke’s aphasia
 Examiner: Do you like it here in Kansas City?
 Aphasic: Yes, I am.
 Examiner: I’d like to have you tell me
something about your problem.
 Aphasic: Yes, I, ugh, can’t hill all of my way. I
can’t talk all of the things I do, and part of the part I
can go alright, but I can’t tell from the other people. I
usually most of my things. I know what can I talk and
know what they are, but I can’t always come back
even though I know they should be in, and I know
should something eely I should know what I’m
doing...
(Akmajian et al. 2001: p. 544)

22. Wernicke’s aphasia
 Fluent, but their speech doesn’t make
any sense.