Chapter 12 Language and the Brain

Neurolinguistics

The study of the relationship between language and the brain is called neurolinguistics.

Language Areas in the Brain

The shaded areas indicate the general locations of those language functions involved in speaking and listening.

Broca’s Area

(1) is technically described as the “anterior speech cortex” or, more usually, as Broca’s area.

Wernicke’s Area

(2) is the “posterior speech cortex,” or Wernicke’s area.

The Motor Cortex and the Arcuate Fasciculus

-(3) is the motor cortex, an area that generally controls movement of the muscles (for moving hands, feet, arms, etc.).

-(4) is a bundle of nerve fibers called the arcuate fasciculus.

The Localization View

It is tempting to conclude that specific aspects of language ability can be accorded specific locations in the brain.

Tongue Tips and Slips

The Tip of the Tongue Phenomenon

The tip of the tongue phenomenon in which we feel that some word is just eluding us. When we make mistakes in this retrieval process, there are often strong phonological similarities between the target word we are trying to say and the mistake we produce called malapropisms

Slips of the Tongue

Another type of speech error is commonly described as a slip of the tongue.

Slips of the Brain

-Perseveration is when one sound is carried over to the next word, so that my favorite song comes out as my favorite fong.

- Anticipation is when a sound is used before its occurrence in the next word, so that roman numeral comes out as noman numeral. 

-Exchange is when sounds change places, so that feel better comes out as beel fetter.

Slips of the Ear

One other type of slip may provide some clues to how the brain tries to make sense of the

auditory signal it receives called slips of the ear

Aphasia

Aphasia is defined as an impairment of language function due to localized brain damage that leads to difficulty in understanding and/or producing linguistic forms.

Broca’s Aphasia

The serious language disorder known as Broca’s aphasia is characterized by a substantially reduced amount of speech, distorted articulation and slow, often effortful speech.

Wernicke’s Aphasia

The type of language disorder that results in difficulties in auditory comprehension is sometimes called “sensory aphasia,” but is more commonly known as Wernicke’s aphasia.

Conduction Aphasia

One other, much less common, type of aphasia has been associated with damage to the arcuate fasciculus and is called conduction aphasia.

Dichotic Listening

An experimental technique that has demonstrated a left hemisphere dominance for syllable and word processing is called the dichotic listening test.

Left Brain, Right Brain

In this process, the language signal received through the left ear is first sent to the right hemisphere and then has to be sent to the left hemisphere (language center) for processing.This non-direct route takes longer than a linguistic signal received through the right ear,which goes directly to the left hemisphere. First signal to get processed wins because of what is generally known as the right-ear advantage for speech sounds.

In contrast, the right hemisphere appears to have primary responsibility for processing

a lot of other incoming signals that are non-linguistic.

The Critical Period

The apparent specialization of the left hemisphere for language is usually described in terms of lateral dominance or lateralization (one-sidedness).

During childhood, there is a period when the human brain is most ready to receive input and learn a particular language. This is sometimes called the “sensitive period” for language acquisition, but is more generally known as the critical period.

Genie

Genie's case is a profound and tragic example of the effects of extreme isolation and deprivation on human development, particularly language acquisition. When Genie was discovered, her situation provided researchers with a unique, albeit ethically complex, opportunity to study the impacts of deprivation on language development and the brain.