Linguistics: Neurolinguistics

What is Neurolinguistics?

•      Neurolinguistics is the study of the biological and neural foundations of language.

•      The research is often based on data from atypical or impaired language and uses such data to understand properties of human language in general.

The brain

•      A brain composed of right hemisphere and left hemisphere, and connected by corpus callosum.

•      They operate contralaterally.

•      The surface of the brain is called cortex. It is often called as “gray matter” and/or the “decision-making”.

•      Somewhere in the cortex, the grammar is resided to represent our knowledge of language.

Localization

•      Proposed by Franz Joseph Gall, in the early nineteenth.

•      It is the idea that different cognitive abilities and behaviors are localized in specifics parts of the brain.

•      The Gall’s view has been upheld by scientific investigation of brain disorder.

Broca’s aphasia

•      Language disorder caused by the injuries to Broca’s area.

•      Broca’s area is localized to the front part of the left hemisphere.

•      The aphasia is characterized by labored speech, word-finding difficulties, and agrammatic speech, it affects a person’s ability to form sentences with the rules of syntax.

Aphasia

•      Language disorder that results from brain damage caused by disease or trauma.

•      There are two kinds of aphasia, those are Broca’s aphasia and Wernicke’s aphasia.

•      It based on the lateralization of language proposed by a French surgeon, Paul Broca (1860) and a German neurologist, Carl Wernicke (1870s).

Wernicke’s aphasia

•      Language disorder caused by the injuries to Wernicke’s area.

•      Broca’s area is localized to the temporal lobe of the left hemisphere.

•      The aphasia is characterized by semantically incoherent speech, difficulty naming objects, and lexical errors.

Other forms of aphasia

•      The kind of aphasia related to reading is called dyslexia.  There are two kinds of dyslexia, those are  developmental dyslexics and acquired dyslexics

•      Another form is anomia, a severe TOT (tip-of-the-tongue).

•      For deaf signers, the aphasia affects the producing of the sign, even though sign language is a visual language. 

Evidences of lateralization

•      Dichotic listening, an experimental technique that uses auditory signals to observe the behavior of human’s hemisphere.

•      Brain imaging technology that can reveal lesions in the living brain, such as CT scan, MRI, PET scan, etc.

•      ERPs (event-related brain potentials) measuring technology.

Critical-age hypothesis

•      Assumes that language is biologically based and that the ability to learn a native language develops within a fixed period, from birth to middle childhood.

source :  Indah Lestari

(source: Fromkin, Intr. to language)