Language and the Brain Lynn W. Zimmerman, PhD

Neurolinguistics Study of the biological and neural foundations of language

Human Brain Cortex Decision making area Receives messages from all sensory organs Initiates all voluntary actions Memory storehouse Grammar resides there

Brain hemispheres Left cerebral hemisphere – controls right side of body Right cerebral hemisphere - controls left side of body Corpus callosum –serves as a bridge for info transfer between hemispheres

Aphasia Aphasia – “any language disorder that results from brain damage caused by disease or trauma” (p. 38) Lateralization – “any cognitive function that is localized primarily on one side of the brain” (p. 38) Modular - It appears that language is organized in modules.

Broca’s Area Front part of left hemisphere Broca’s aphasia agrammatic generally “affects the person’s ability to form sentences with the rules of syntax” (p.39). Also have trouble understanding sentences whose meanings are heavily syntax based.

Wernicke’s Area Posterior of left hemisphere Wernicke’s aphasia jargon aphasia generally semantically incoherent have problems naming objects and finding words

Brain Plasticity and Lateralization in Early Life distinct evidence of left hemisphere dominance for language evidence that the right hemisphere plays some role in early language development

Other Experimental Evidence Ipisilateral stimuli – same side show that the left hemisphere is lateralized for language but not necessarily for sound. Event-related brain potentials - “electrical signals emitted from the brain in response to different stimuli (events” (p. 48) demonstrate the left hemisphere’s connection to language, particularly grammar. Japanese writing systems Kana – based on sounds – tends to be processed in the left brain Kanji - based on symbols - tends to be processed in the right brain

The Autonomy of Language Specific language impairment (SLI) children with no other cognitive dysfunctions may have specific language disorders supports notion that grammar is localized and separate from other cognitive functions Genetic basis of language Evidence from various types of disorders “strongly supports the view that the grammatical aspect of the language faculty is an autonomous, genetically determined module of the brain.” (p. 52)

Language and Brain Development Critical Period – Critical-age Hypothesis Between birth to middle childhood, language acquisition results in native proficiency. Hypothesis there is “a biologically determined window of opportunity during which time the brain is prepared to develop language.” (p. 55) Seems specifically related to grammar - after the critical period, there is “selective acquisition of certain components of language.” (p. 55) Seems to be an external trigger to develop language ability Supports the notion that communication and language are not the same.

The Evolution of Language No real historical evidence of how language developed. Divine origin of language – most religions have a belief in the divine origin of language Monogenetic theory of language origin – the notion that “all languages originated from a single source.” (p. 59)  Certain physiological changes including changes in brain structure which helped language develop Incremental? Appeared all at once? Who knows?

References Fromkin, V., Rodman, R., and Hyams, N. (2007). An introduction to language. 8th ed. Boston: Thomson Wadsworth.