LINGUISTICS
LINGUISTICS
Linguistics is the study of language. There are many different
kinds of linguistics studies—each with its own theoretical
perspectives and methodologies. Some of these adopt a neuroscience
approach and use the case study method; the researchers study the
language-related deficits of patients who have suffered brain
damage. Others implement various network models of how language
information is represented and processed. Some linguists take on a
developmental orientation: they examine how language ability grows
and changes with time during the development of the individual. Still
others who study linguistics are philosophers who ask questions about
the nature of language and of the relationship between language
and thought.
LINGUISTICS

The psychological study of language is often known as
psycholinguistics. The person most responsible for
providing insight into the intricacy of language as a
system is Noam Chomsky, the linguist who revolutionized
the study of language and who has been making major
theoretical contributions to linguistics over the last forty
years (Chomsky, 1957, 1965, 1981, 1986). A crucial
insight was that people routinely produce and
understand utterances that are completely new to them,
ones they have never said before or had said to them.
LINGUISTICS


This creativity that characterises language must
imply that language users have a set of rules which
allow them to tackle any sentence that comes along.
It is this set of rules, known as the grammar, that
linguists like Chomsky set out to discover.
Psychologists have been interested in the grammars
developed by linguists because of the possibility
that they will help in understanding what goes on in
speaking and listening.
DISORDERS OF
SPEECH AND
LANGUAGE
SPEECH
DISORDERS
A speech disorder is a problem with fluency,
voice, and/or how a person says speech sounds.
Common speech disorders are:
 DEVELOPMENTAL VERBAL DYSPRAXIA
Developmental verbal dyspraxia refers specifically to a
motor speech disorder. This is a neurological disorder.
Individuals suffering from developmental verbal apraxia
encounter difficulty saying sounds, syllables, and words. The
difficulties are not due to weakness of muscles, but rather on
coordination between the brain and the specific parts of the
body.
APRAXIA
Apraxia of speech is the acquired form of verbal
dyspraxia caused by brain injury, stroke or dementia.
 DYSARTHRIA
Dysarthria is a motor speech disorder that results from
a neurological injury. Some stem from central damage,
while other stem from peripheral nerve damage.
 SPEECH SOUND DISORDER
Speech sound disorders may be of two varieties:
Articulation(production of sounds)- may take the form
of substitution, omission, addition, or distortion of
normal speech sounds.

Phonological processes(sound patterns)- may involve
more systematic difficulties with the production of
particular types of sounds, such as those made in the
back of the mouth, like “k” and “g”.
 STUTTERING
Stuttering is a disruption in the fluency of an individual’s
speech, which begins in childhood and may persist over a
lifetime. Stuttering is a form of disfluency. Disfluencies may
be due to unwanted repetitions of sounds, or extension of
speech sounds, syllables, or words. Disfluencies also
Incorporate unintentional pauses in speech, in which the
individual is unable to produce speech sounds.
LANGUAGE
DISORDERS
Since ancient times it was known that damage to the brain
could affect language functioning but a
major breakthrough occurred in 1861 when Paul Broca, a
surgeon and anthropologist in Paris reported an autopsy he
had carried out on the brain of a man who had had severe
loss of language for more than twenty years. The man’s
nickname was ‘Tan’ because, although he could answer some
questions with gestures, all he could say were a few swear
words and the syllable ‘tan’. Broca found that an infection
had left ‘Tan’s’ brain with a large abscess in the left frontal
lobe. Based on this case and on others he subsequently
studied, Broca concluded that the two hemispheres of the
brain were not identical in function and that the left
hemisphere was the one involved in language.
Loss of speech was localized in the left frontal lobe, more
specifically in the posterior portion of the lower frontal lobe, the
area believed to be at least partly responsible for language
production capacity, now known as Broca’s area. While Tan’s
language impairment appears to have been a very severe one, the
language of patients with Broca’s aphasia is usually described as
being slow, laborious and non-fluent; speech is produced in short
phrases with little variation in intonation and with frequent
mispronunciations. People with this disorder often seem to grope
for words but the words they do manage to come out with are
usually meaningful. They produce what is called “agrammatic
speech.” They generate strings of nouns and some verbs, but
without any of the filler words such as “the” or “is.” They also fail to
make words plural or to use verb tenses.
Their sentences are short and broken up by many pauses, which has
sometimes earned this kind of speech the nickname “telegraphic” or
“nonfluent” speech. An example of a brief exchange with a man with
Broca’s aphasia reported by Gardner(1977):
‘What happened to make you lose your speech?’
‘Head, fall, Jesus Christ, me no good, str…str…Oh Jesus…stroke.’
‘I see. Could you tell me, Mr Ford, what you’ve been doing in the
hospital?’
‘Yes, sure. Me go, er, uh, P.T. nine o’cot, speech…two
times…read…wr …ripe, er, write…practice…getting better.’
‘And have you been going home on weekends?’
Why yes…Thursday, er, er, er, no, er, Friday…Barbara…wife…and,
oh, car…drive…purnpike…you know…rest and… tee-vee.’
‘Are you able to understand everything on televsion?’
‘Oh, yes, yes…well…almost.’
Within a few years Carl Wernicke had noticed that some
forms of language disturbance present a different picture
and not all involve Broca’s area. He described a form of
aphasia now known as Wernicke’s aphasia in which the
person’s speech is fluent but has little informational value
and in which there is poor comprehension of language. This
type of speech sounds normal in the sense that its rate,
intonations, and stresses are correct, but it is lacking in
content or meaning. These patients have major problems
with comprehending speech and also demonstrate difficulty
in reading and writing. This form of aphasia is associated
with damage in the upper part of the left temporal lobe.
The following excerpt (again from Gardner, 1977)
demonstrates why this form of language disorder is
sometimes known as ‘fluent aphasia’:
‘What brings you to the hospital?’ I asked the 72-yearold retired butcher four weeks after his admission to
the hospital.
‘Boy, I’m sweating, I’m awful nervous, you know, once in a
while I get caught up, I can’t mention the tarripoi, a
month ago, quite a little, I’ve done a lot well, I impose a
lot,
while, on the other hand, you know what I mean, I have to
run around, look it over, trebbin and all that sort of stuff.’
Wernicke (1874) also theorised about the
neurological organisation for language, basing his
ideas on a model in which Broca’s area contained
motor memories, memories of the sequences of motor
movements needed to articulate words and thus was
responsible for speech output. Wernicke suggested
that the area that now bears his name recognises the
sounds of words, being the location that holds
memories of the sound patterns of words.
Wernicke also speculated about what might happen if the
connecting pathways between Broca’s area and
Wernicke’s area should be damaged, but the areas
themselves remain intact. He suggested that comprehension
of language and production of speech would not be
impaired but there would be a difficulty in repeating back
what had just been heard, because sound images received
by Wernicke’s area could not be transmitted forward to
Broca’s area to be produced.
More recently it has been established that some people
with aphasia do fit this picture, a pattern of aphasia
which is referred to as conduction aphasia
(Geschwind,1965). When asked to repeat back a
sentence these people often make phonological errors,
leave out words, substitute other words or may have
extreme difficulty in saying anything. A large tract of
fibres, known as the arcuate fasciculus, does connect
Broca’s area with Wernicke’s area and damage to this
tract and surrounding tissues is indeed found in cases of
conduction aphasia.
Wernicke’s model was elaborated on by Lichtheim (1885),
who argued that there was a third centre for language
processing, a ‘concept centre’ which stores the mental
representations of objects and associates them with words.
Geschwind (1972) more recently postulated the location
of such a centre in an area of the parietal lobe known as
the angular gyrus. Disruption could occur not only because
of damage to Broca’s area and Wernicke’s area and to
the fibres linking them, but also, it was thought, to the
fibres linking the concept centre with Broca’s and with
Wernicke’s areas.
It was postulated that if there was disruption to the
connections between the concept centre and Broca’s area then
the person’s speech would be very disrupted. However, they
should still be able to repeat back language they have heard
if the connection from Wernicke’s area to Broca’s area is still
intact. Such a pattern of language disorder has been found
and is known as transcortical motor aphasia. The person has
the same impairment of speech as in Broca’s aphasia but is
able to repeat what has just been said; in fact that person
often seems to have a compulsion to repeat back what is
heard, a characteristic known as echolalia.
Using similar reasoning, if there was disruption to the
links between Wernicke’s area, where the sounds of
words are processed, and the concept centre, but the
links from Wernicke’s area to Broca’s area were intact,
then the effect might be that the person could not
interpret the meaning of words but could still repeat
back what had been said. Again, such a pattern of
language disorder has been observed and is known as
transcortical sensory aphasia. The person with this type
of disorder has a similar disruption to the ability to
understand language as someone with Wernicke’s
aphasia, but is able to repeat back language and shows
echolalia.
Another particularly striking pattern of language disruption
in aphasia is one that has been found to occur in rare cases
where Broca’s area, Wernicke’s area and the connection
between them are intact, but they are essentially cut off from
the rest of the brain. In these cases the ‘ring’ of tissue that
surrounds those areas becomes starved of oxygen, being
relatively far from the main artery which supplies it. Lung
disease and some toxins, including carbon monoxide
poisoning, can cause this loss of oxygen and of other
nutrients causing the ring of tissue to become permanently
damaged.
The effect of such ‘isolation of the language zone’
(Geschwind et al., 1968; Caplan, 1992) is that the person
loses the ability both to understand and to produce speech
beyond a few stereotyped expressions but has some
preservation of the ability to repeat sentences back
verbatim. Some ability to recognize words must therefore
be preserved but the person is unable to understand the
meaning of what he or she hears and repeats.
Other important types of language disorder are those of
acquired dyslexia (also known as ‘alexia’) where the
person experiences loss of the ability to read after brain
injury, and dysgraphia (also known as ‘agraphia’) where
the person loses the ability to write. What actually occurs in
these disorders is essentially that the visual areas of the brain
become disconnected from the language areas because of
damage to the angular gyrus, an association area in the brain
that is important for the association of visual stimuli with
linguistic symbols.
SPEECH DISORDERS