Download Week 7 -Chapter 13 – NeuroLinguistics

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Chapter 13
Neurolinguistics
Study of Language and Brain
Speech is the representation of the mind, and writing is the representation of speech. Aristotle
What to find in this chapter
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Structure of Brain
Aphasia and Anomia
Lateralization
Dichotic Listening
Mechanisms of Speech
Neuro-Linguistic Programming (NLP)
Teaching through Neurolinguistics
13.0 Introduction
If we had to do a savage experiment on a person by mutilating him piece by
piece in order to find out which bodily organ houses language faculty, what do you
think the result would be? The obvious answer is head: more specifically the brain,
which is contained in the head. Thankfully, with the development of sciences we
need not do such an inhuman experiment to prove our point.
Recall from the first chapter that one of the major features of language was
that language is a product of mind and that it is produced as a result of the mental
operations in the brain.
In this chapter we elaborate on the relationship of language and brain so as
to probe the physiological underpinnings of language: we would be pursuing
questions like:

Where is language located in the brain?
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What are building blocks of the organ called brain?
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How does the nervous system function to encode and decode speech and
language?
This chapter begins with a description and scope of neurolinguistics, followed by
brief information on the structure of brain. In the rest of the chapter, the question is
investigated whether specific parts of the brain have specific functions. To support
the position that it is so, various experiments and techniques are explained. Finally,
three models are offered in order to account for the paths and procedures that take
place during speech production.
13.1 Neurolinguistics
Neurolinguistics is the term used to refer studies describing the physical
relationship between language and brain. The term came about as result of the
blending of the medical term ‘neurology’ and ‘linguistics’. Neurology is a branch of
medicine that scientifically studies the anatomy and (mal)-functions of brain.
Neurolinguistics is more a branch of neurology than of linguistics as mainstream
linguistic studies usually are confined to the output, i.e. speech as produced by
speakers. Therefore, neurolinguistic information is largely dependent on case
studies and experiments done in neurology laboratories.
There are times however when neurologists have to consult with linguists in
order to appreciate the subtle differences their patients produce. For instance, they
need to know what parts of speech are if they wish to better describe the type of
language their patients produce, or what is phonology, morphology or syntax.
13.2 Structure of Brain
Brain is no doubt the most indispensable, sensitive, and complex organ of
the body. We will not go into the intricate aspects of its physical structure nor all of
its functions for the human body. For our purposes, however, we will mention only
those areas that are relevant for language.
We know from newspaper reports that some seriously ill patients are
described as “brain dead”. A brain dead patient is an otherwise fully functional
person except that his brain functions are severed to a point where the patient
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experiences total loss of consciousness, which is enough evidence to show that
brain is the most important organ.
Brain is located in the upper part of the head, protected by a spherical shape
of bones known as skull. In between the bones and the brain lies a thin layer of
tissues to regulate heat and cold. Brain contains about 10 billion neurons, which are
the building blocks of the brain. The neurons are interconnected through billions of
fibers. A neuron can be conceptualized as a nerve cell containing information of any
kind. Continuous flow of oxygen through thousands of tiny veins is supplied to the
brain so that brain can keep functioning normally.
The size of the brain in men is generally greater in about one fifth than in
women. Average brain weight for women is about 450-500 grams while it is about
550-600 grams for men. Larger brain size does not appear to play any positive or
crucial role whatsoever in speech given the popular view and observation that
women speak in longer durations than men.
Brain cannot be conceptualized in isolation: it is part of the nervous central
system that controls the body and also it is the most functional part of it. The central
nervous system consists of two main organs: the spinal cord and the brain. Spinal
cord can be conceptualized as the arm of the brain to control physical movements of
the body and it extends through the skeleton to all areas in the body.
When looked from outside, brain looks like a watermelon cut in half, which is
further divided into halves, called ‘hemispheres’. The two hemispheres are
connected by a cord, called ‘corpus callosum’1, which is like an electrical cable that
enables the essential communication between the two hemispheres.
One basic operation of the two hemispheres is that the right hemisphere
controls the movements of the left part of the body while the left controls the
movements of the right part of body. That is, if a serious damage is inflected in the
right hemisphere, it is the left part of the body that is paralyzed or seriously
handicapped.
Both hemispheres work together though at times one is more involved in
some mental functions while the other less. If the left hemisphere carried out more
mental functions in some people, they are said to be ‘left hemisphere dominant’ and
visa versa. For instance, for 95 % of right-handed people it is the left hemisphere
1
The pronunciation for it is / /
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that is dominant. This relationship, however, is not symmetrical. This does not mean
that the opposite holds true for left-handed people. Actually, left hemisphere is
dominant for more than 60 % of left-handed people.
Neurology is still in its infancy: we know very little about the functions of the
brain, and research is continuously being carried out to explore the depths of the
brain functions.
Localization
The question that whether certain parts of the brain are “assigned” certain
abilities, capacities, or functions has been debated for about two centuries. If
specific parts of the brain are identified having different human abilities or
competencies, it is then said that certain abilities are ‘localized’ in the brain.
Though there are differing views on the topic ranging from the extreme
argument that all parts of the brain participate in all operations of the body to the
argument that precise areas are responsible for specific functions. It appears from
the more recent as well as some earlier studies that the latter view is more
favorable, at least, so far as linguistic operations are concerned.
Aphasia
One of the pioneers of research on brain was a French surgeon named Paul
Broca. He presented evidence in a conference in Paris, France, in 1861 that it is the
left hemisphere with which we speak. Thus, the first piece of credible evidence was
favoring the view that language functions are localized. How did he obtain evidence
to show that language is localized? The patients he worked on had injuries on the
front part of the left hemisphere and as a result of the injuries these patients had
difficulty in expressing themselves (see figure). Their speech was like a telegraphic
speech similar to what two year old children would speak. The discovery pointed to
the “house” of language in the brain while it identified an impairment or physical
disorder in the patient. This impairment is known as ‘aphasia’.
Aphasia then can be described as a language disorder that results from
damage to certain parts of the brain responsible for language functions. Aphasia can
also occur either as a result of a stroke or heart attack. This type of aphasia, named
Broca’s aphasia, impairs
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Speech and Comprehension.
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Reading and Writing.
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Individuals with Broca’s aphasia can still speak sensibly and in short
phrases. They tend to use content words such as verbs, nouns and so forth while
omitting function words such as and, the, is, and the like. The following is a typical
example from aphasic speech, whose interpretation depends heavily on the context
of speech.
Speech of Individuals with Broca’s Aphasia
Interpretation
I will take the dog for a walk.
Walk dog.
You take the dog for a walk.
The dog walked out of home.
Later in 1873 another surgeon Karl Wernicke from Germany was presenting
evidence relating to language disorders: but this time the location of the injuries was
not the front part of the left hemisphere, but the back part of the brain. The actual
area involved was slightly larger than that of Broca’s area.
Speech of Individuals with Wernicke’s Aphasia
Interpretation
You know that smoodle pinkered and that I want to
The dog needs to go out so I
get him round and take care of him like you want
will take him for a walk
before.
Wernicke’s aphasia exhibits features of speech that seem to have the
opposite characteristics to those of Broca’s aphasia. Individuals with Wernicke's
aphasia tend to speak in long sentences that may have no clear meaning. Though
wordy their sentences are, again the circumstances under which the speech was
made needs to be known well to interpret the sentences.
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LEFT HEMISPHERE: Broca’s Area and Wernicke’s Area
Broca’s Area
FRONT
BACK
Wernicke’s Area
BROCA’S APHASIA
prevents a person from producing
WERNICKE’S APHASIA
loss of the ability to understand language
speech
person can understand language
Clear but non-sensible speech
words are not properly formed
Longer sentences with considerable
grammar
Unclear pronunciation
Considerable grammar with little
semantics
Speech is slow and broken.
These two pioneering studies and many more that replicated them proved
beyond doubt that language is localized in two specific areas in the left hemisphere:
Broca’s area is close to the very front part while Wernicke’s area is close to the back
part, though considerably larger than the previous one.
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Overall, then, we are not speaking of a complete loss of linguistic capacity
with the two types aphasic patients; rather, it is a partial one that blocks smooth and
effective communication. Despite their injuries, they can still produce and hear
language.
Anomia
It should then be clear that aphasic patients are unable to remember the
words they wish to use. The loss of the ability, to a great extent, to call words on
demand is called ‘anomia’. In such cases, aphasic speakers may replace other
words or phrases to compensate the deficiency.
The strategies they use reveal how their lexicon is organized in terms of
pronunciation, grammar or semantics. Fromkin and Rodman (1983:366) claim, on
the basis of available data from aphasic type of speech, that phonetic and
phonological components of language are separate. They cite evidence in which
aphasics will say democracy when they are asked to read liberty:
This reveals the reality of semantic features. It is almost as if the patient in reading
went to the stored written word and “looked up” its meaning and then immediately
went to another word which shared these semantic features abd read that word
instead. (ibid. p.366)
Lateralization
Dominance
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The following figure is adapted from Akmajian (1984).
LEFT HEMISPHERE
Language
Verbal
Sounds
Speech
Reading
Writing
RIGHT HEMISPHERE
Holistic
processing
Nonverbal
sounds
Calculation
Visuospatial
skills
Recognition
Thought
Melodies
Right visual
field
Left visual
field
Corpus Callosum
Experiments with Brain
Various experiments have been carried out to find out the exact or relative
positions of linguistic functions in the brain. These experiments involve studies with
patients whose corpus callosum was sectioned, injecting chemicals into the brain,
electrical stimulation of the brain, and listening to two different expressions
simultaneously.
Dichotic Listening
In dichotic listening, as the term suggests, subjects are given two pieces of
listening text at the same time, one to the left ear, the other to the right ear. For
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instance, subjects can be asked to report what they heard soon after they are
subjected to the listening of student through the left ear and teacher through the
right ear. Consider the table for the experiment results that involve the testing of
verbal as well as nonverbal sounds.
Verbal Sounds
Nonverbal Sounds
Dichotic Listening Experiments Results
Listening - Left Ear Listening - Right Ear
Student
Teacher
Book
Paper
Cough – cough
Ahh - ahh
Police siren
Car horn
Report Result
Teacher
Paper
Cough – cough
Police siren
Generally speaking, subjects who heard teacher through the right ear and
student through the left reported to have heard teacher more often. This result,
coupled with others, indicated that verbal sounds are processed in the left
hemisphere. When subjects are subjected to nonverbal sounds, the opposite turned
out to be the case. For instance, cough – cough was spoken to the right ear while
ahh – ahh was to the left ear. The result was that subjects reported to have heard
better cough – cough. One can conclude from these studies that the processing of
verbal sounds is carried out in the left hemisphere and the nonverbal sounds in the
right, which is another piece of evidence for the existence localization or
specialization in the brain.
Split Brains
There had to be occasions when the injured patients’ corpus callosum had
to be removed to offer them some relief from pain, which produces a situation in
which the communication between the left and right hemispheres is broken down.
Experiments on such patients showed that information sensed by the left side of the
body (which arrives at the right hemisphere for processing) cannot be verbally
expressed.
If an apple is put in the left hand of a split-brain human and his vision is cut off, he
cannot describe the object. The right brain senses the apple, and is able to distinguish
the apple from other objects, but the information cannot be relayed to the left brain for
linguistic description. But if the same experiment is repeated and in addition a banana
is placed in the right hand, the subject is able to describe the banana verbally, though
he is still unable to describe the apple. (Fromkin and Rodman, 1983:369)
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Brain Imaging Technique
With the development of technological devices, the relationship between
language and brain can be more accurately studied. States of the brain during
linguistic activity can be “photographed” in the form of images if do not mind the
term. One of these brain imaging techniques is PAT, standing for Positron Emission
Tomography. Images produced by PAT show the physical activities taking place in
the brain during language activity. One of these activities is that the pace of blood
flow increases in those areas where language is used, either in listening or
speaking. PAT images indicate that such observable changes do not only take place
in the left hemisphere but also in the right. In other words, though the right
hemisphere is not dominant in language, it still has a part to play in language
reception and production.
Chemical Injection
In 1949 Wada introduced a chemical technique in determining the location
of speech. In his experiment, he used a chemical called ‘sodium amytal’, which is an
anesthetic to temporarily put the brain to sleep. He injected this chemical into the
arteries that supply blood to both hemispheres. When he injected the chemical into
the left arteries of patients who had the language ability in the left hemisphere, they
could not speak when they were asked. However, the same patients could speak
and answer questions when the injection was made the right arteries that supply
blood to the right hemisphere. Many more similar studies confirmed that language is
localized, and in most people language is localized in the left hemisphere.
Electrical Stimulation
Perhaps the most elaborate of a series of pioneering studies was carried out
by Penfield and Roberts (1959) in Canada. They were not particularly researching
the relationship between language and brain as they were trying to give relief to
patients who were experiencing seizures (attacks, fits) in their brains. Part of the
task of giving relief necessitated a surgical removal of the some parts of the brain.
Because they did not want to remove areas responsible for language functions, they
had to first identify those areas responsible for speech.
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It is in this phase of the brain research that identified and confirmed the
fundamental areas where speech processing is carried out. They applied electrical
stimulation to various areas in the brain which produced quite different reactions in
the patients. For instance, when the electrical stimulation was applied to what is
known as motor area, subjects experienced physical changes in the form of muscle
contracting and trembling, or parts of their body lost sensitivity such as touching.
This shows that the motor area is the centre of command to direct a person’s
physical activities. As far as language is concerned, using vocal organs to speak
gets instructions from the motor area.
More importantly, perhaps, when electrical stimulation was applied to areas
known as Broca’s and Wernicke’s areas, Penfield and LaMar engaged their subjects
in speaking. The result was that their patients experienced either immense difficulty
in speaking or produced cries that resembled language more than any other of
sound. Once again for all, they established that Broca’s area, Wernicke’s area and
the motor area were three major centers involved in speech processing and
production.
W. Penfield
It is time now to examine what the paths / procedures are followed in the
brain during the process speech is generated.
Mechanics of Speech
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The question of how speech comes to materialize is answered to a great
extent by Geschwind (1972). According to Geschwind, speech occurs as a series of
steps taking place in several parts of the left hemisphere. The type of steps can
change depending on the stimulus that prompts a subject to speak. If the stimulus is
a word that is heard, one particular series of steps are followed; if it is a written word,
then another series of steps. If there is no verbal stimulus, yet another path is
followed. In summary form, they are:

Speaking without any verbal stimulus

Speaking a word that is heard

Speaking a word that is written
Let us look at each of these in turn; first, speech without any verbal stimulus.
Though no verbal stimulus exists here, stimuli can be either physical or
psychological. Imagine someone who is hungry and wishes to say “I’m hungry.”
There appear to be two basic phases: 1) Conceptualization, and 2) Speech.
Conceptualization or the basic structure of utterance is generated in Wernicke’s area
and straight after is sent to Broca’s area for the utterance to be encoded before it is
forwarded to the motor area, which activates the vocal organs.
SPEAKING WITHOUT ANY VERBAL STIMULUS
Steps
Step 1
Phases
Conceptualization
Features
Utterance Generated
Action
Location
Step 2
Step 3
Step 4
Speech
Utterance decoded
Readiness to
Vocal organs
speak
activated
Articulatory information
Activated information
Action taken to
The word
activated in
passed onto
speak
spoken
Wernicke’s area
Broca’s area
Motor area
Actual Speech
The second type of speech involves the repetition of word heard. When
subjects are asked to listen to a word, the message is sent to the auditory area
responsible for processing the incoming pronunciation. For the full processing to
take place, the pronunciation is transmitted to Wernicke’s area as it is responsible
for verbal language processing. Because the task is to repeat the same word, this
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information (pronunciation) is passed onto Broca’s area for it to be conceptualized.
The intention to repeat is converted into action when motor area receives it. Once
the motor area instructs the vocal organs, speech occurs.
SPEAKING A WORD HEARD
Step 1
Phases
Step 2
Step 3
Hear the word
Action
Location
Step 4
Step 5
Speak the word
Pronunciation
Articulatory
Activated
Action
The word
received in
information
information
taken to
spoken
activated in
passed onto
speak
Wernicke’s area
Broca’s area
Motor area
Auditory area
Speech –
Vocal
organs
The third type of speech in which a visual or written stimulus is involved. In
other words, reading first and replicating the read word in speaking form. In the
reading phase, written symbols are first received in the visual area, responsible for
almost all the visual input into the brain. The area known as ‘angular gyrus’2
functions like a filter and sends it to Wernicke’s area for linguistic processing. Once
the message/information in symbols is converted to language in this area, it is then
forwarded to the Broca’s area.
As for the speaking phase, it is in Broca’s area that abstract sounds symbols
correspond to the written symbols are activated. Then the information is passed on
the motor area responsible for controlling the bodily actions in the body. According
to the instructions received from the motor area, vocal organs work together to
produce the speech.
SPEAKING A WORD READ
Step 1
Phases
Action
2
Step 2
Step 3
Step 4
Reading
Step 5
Step 6
Speaking
Written
Written
Written
Same abstract
Action is
The word
symbols
symbols
symbols
symbols
taken to
spoken
received in
activated in
decoded in
activated in
speak
The pronunciation for it is / /.
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Location
Visual area
Angular
Wernicke’s
gyrus
area
Broca’s area
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Motor
Speech –
area
Vocal
organs
Three most important areas emerge to be responsible for speech before it is
emitted through the vocal organs:

Wernicke’s Area →
Center for Utterance Generation, Auditory
Representation, Interpretation and Decoding

Broca’s Area →
Center for Encoding and Conceptualization

Motor Area →
Center for Command and Instructions
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NLP: Neuro-Linguistic Programming
In the two experiments described above, the stimuli for the subjects to speak
were auditory (heard) and visual (written symbols), respectively. A person can
normally be stimulated through his five senses: seeing, hearing, touching, smelling,
and tasting.
BRAIN’S FIVE SENSES
Seeing
Hearing
Touching
Smelling
Tasting
Visual
Auditory
Kinesthetic
Olfactory
Gustatory
There have been attempts lately to utilize all or the preferred senses of
people in all areas of learning and personal development. This is what NLP is about:
identify the most or the more preferred channels (systems, senses) of language
learners and design the syllabus according to neurolinguistic needs of the learners.
Instead of relying heavily on visual or auditory techniques of teaching,
teachers can vary their techniques and procedures by including activities based on
kinesthetic, olfactory and gustatory.
Basically, NLP teaches us two things:
1. Learners have different preferred systems of experiencing the world
(knowledge, teaching, lesson, etc.), and
2. Learners may like to use, and so get stimulated to learn, various senses to
learn more efficiently as they get involved in real-life like tasks. This will also
modify a monotonous pattern of learning.
Practitioners of NLP believe that if activities are designed in a way to tap
different or the best functioning areas of brain, learning can be maximized.
Conclusion
No doubt, language is located in various locations in the left hemisphere
with the right hemisphere contributing and perhaps complementing the tasks of the
left. This, however, should not rule out the possibility of other areas having
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meaningful contributions, though minimal. We can now safely say that the most
important areas for speech are: Broca’s area, Wernicke’s area and the motor area.
Knowledge of the relationship between language and brain will certainly
benefit the language teacher, as we now know that various abilities are localized.
Activating various areas in the brain through different activities for learners can help
involve them in the learning process. Further, when devising activities in classroom,
preferred ways of using the five senses can be identified and thus be implemented
through the guidance of neuro-linguistic programming.
Teaching through Neurolinguistics Knowledge
Activity 1
References and Further Reading
Fromkin, Victoria and Rodman, Robert (1983) An introduction to language. New
York: Holt.
Geschwind, N. (1972) Language and the brain. Scientific American, 226, 76-83.
Harley, Trevor (2001) (2nd ed.) The psychology of language: From data to theory.
East Sussex: Psychology Press.
Lamb, Sydney M. (1999) Pathways of the brain: The neurocognitive basis of
language. Amsterdam: John Benjamins.
Penfield, Wilder and Roberts, LaMar (1959) Speech and brain mechanisms.
Princeton: Princeton University Press.
Wada, J. (1949) A new method for the determination of the side of cerebral speech
dominance. Medical Biology, 14, 221-222.
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