Linguistics: Neurolinguistics Indah Lestari (source: Fromkin, Intr. to language)

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.

The brain

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.