1. The Nature of Human Language
Neurolinguistics: The Brain and Language

2. Neurolinguistics
The branch of linguistics that studies the biological and neurological foundation of language.
Researches humans and other primates
Often uses data from atypical or impaired language users to understand the properties of human language in general.

3. The Human Brain The cortex Makes decisions
Initiates voluntary and involuntary actions
Houses our knowledge of language

4. The Human Brain Language seems to be located in the left hemisphere.
Two hemispheres: left and right
Left hemisphere controls right part of body
Right hemisphere controls left part of body
Joined by corpus callosum: allows two hemispheres to talk to each other
Language seems to be located in the left hemisphere.

5. Lateralization in early life
Lateralization = localizing specific functions to one hemisphere or the other
Left side of babies’ brains lights up when exposed to language people are born with left side controlling most language (right controls some)
Plasticity in early life babies’ brains can adapt if they need to (clip)
Babies with left hemisphere removed show almost no problems with language—right side takes over
Adults with left hemisphere removed lose most language function.

6. Aphasia
Any language disorder that results from brain damage (disease or injury).
Damage to Broca’s area or Wernicke’s area (left side of brain) seems to cause aphasia.
Not usually total language loss.
We study aphasiacs to understand which parts of the brain control which parts of language.

7. Aphasia Broca’s aphasia = damage to Broca’s area
Affects a person’s ability to form a sentence within the rules of syntax and find the right words
Agrammatic language: lacks function words (articles, prepositions, pronouns, etc.)
“Me go, er, uh, PT [physical therapy] none o’cot, speech…two times…read…ripe…rike…uh write…practice…get…ting…better.”
Broca’s aphasia patient 9 months after stroke and 5 years after stroke

8. Aphasia Broca’s aphasia: Confused by passive voice
“The cat was chased by the dog.”

9. Aphasia Wernicke’s aphasia
Syntax and grammar sound right, but the words don’t make sense.
Difficulty naming objects
Use the wrong words or nonsense words:
“I felt worse because I can no longer keep in mind from the mind of the minds to keep me from mind and up to the ear which can be to find among ourselves.”
“I’m a male demaploze on my own. I still know my tubatoys what for I have that’s gone hell and some of them go.”

10. What does aphasia teach us about language and the brain?
The brain makes connections between semantically-related words (words that are related in meaning)
boy and girl, table and chair, cheer and clap
The brain makes connections between words that sound alike
Pool and tool, sable and table, crucial and crucible

11. What does aphasia teach us about language and the brain?
Aphasiacs have difficulty speaking, but don’t have any other impairments (hearing, writing)
Language isn’t centralized in one area of the brain
Hearing, grammar, and words are all located in different parts of the brain.

12. The Critical Period
The critical age hypothesis: the ability to learn a native language develops between birth to middle childhood
Children don’t need specific language instruction, but they need exposure to language.
Language develops quickly and easily during critical age, without intervention
Children deprived of language develop atypically.

13. The Critical Period
Critical age hypothesis: tested by experiments in nature
“Genie”
Confined in a room with minimal human contact from 18 months – almost 14 years
Knew no language, not able to speakalthough language acquisition is a biologically-based ability, it must be triggered by the environment

14. The Critical Period “Genie”
Eventually able to learn large vocabulary (concrete and abstract words)
Never acquired a grammatical structure or complex sentences
Man motorcycle have
Genie full stomach
Genie bad cold live father house
Want Curtiss play piano

15. The Critical Period “Genie”
Tests showed language was localized to right hemisphere
Usual language areas atrophy because of lack of stimulation
Genie was a powerful nonverbal communicator  language is not the same as communication.

16. The Critical Period Chelsea
Deaf, wrongly diagnosed as mentally impaired until age 31
Fitted with hearing aides, received extensive language training
Had large vocabulary but never developed a grammar
Showed an equal response to language in both hemispheres  language was never lateralized
Critical period is true for grammar, but not vocabulary