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PART ONE
MECHANISM OF THE SPEECH ORGANS
Introduction
The purpose of this book is to expose students to the basic structure of the speech
producing organs and their functions in terms of making meaningful spoken language.
The speech mechanism is simply the organs of speech coming together to perform a
function. In this instance, it is the spoken language of a particular language whose speech
sounds are combined and recombined meaningfully into words and sentences.
The student in teaching speech to the speech impaired therefore, has the need to
learn the anatomy and physiology of the speech mechanism and acquire the competent
skills to manage these problems which are very common among both children and adults.
These people are those with stuttering or fluency problems, hearing impairment, mentally
handicapping condition (intellectual disability), articulation errors and others who can
hear but have speech problems. This latter group involves the post-stroke patients, the
autistic children and those with any aspect of communication problem. Basic school
children have speech and language problems including spelling and other communication
skills (Donani and Avoke, 1996; Gadagbui, 1996 and 2001; Yemeh, 1997 and Boison,
2000).
Speech difficulties create serious social, emotional and academic problems among
learners at home and at school. For instance, social withdrawal, labeling and namecalling
are some of the punitive measures meted out to victims with speech difficulties.
Belongingness is an integral part of any society therefore, speech difficulties exclude
people from active participation in communication and deprive them of other social
activities. Examples of these can be the inability of the person with speech disability to
share information and the associated joy and sympathy when appropriate. Speech
difficulties also deprive interactants of good communication. Later on in life, speech
difficulties carve professions or jobs for the victims even though these may not be the
desired occupations of the person. To assist people with speech difficulties, as well as
teachers and parents, this book is written to give information on the basis of speech
organs and how they function to produce normal speech. In addition, this book has
information on how to trace problems on speech production and where to source for
remediation.
Based upon this background, the objectives of this book primarily are stated as follows:
- acquire skills in identification of children and adults with speech problems
- acquaint themselves with organs of speech, and
- manage common speech problems among preschool children and post-stroke patients.
What is speech?
Speech is an oral communication in any given language, which involves the use of
meaningful sounds, words or sentences expressing ideas or feelings between a listener
and a speaker. Speech is rule governed and involves meaningful vocal symbols in which
the interactants are engaged in using common codes. Other synonyms of speech are
verbal expressions or spoken language of a given language. Speech is a complex
neuromuscular activity that involves action of over 100 muscles in the head, neck, chest,
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and abdomen. Speech production involves the cerebral cortex specifically, the parietal
lobes, the Broca’s area which is within the left frontal region of the Frontal Lobe,
Wernicke’s Area and the Primary Auditory Area of the Temporal Lobe. The Wernicke’s
area is positioned at the posterior left temporal lobe near the auditory association areas of
the brain. The Primary Auditory Area is situated by the inferior portion of the lateral
fissure (See Figure 1). In addition, the Central Nervous System and the Peripheral
Nervous System are involved: the cerebrum and the cranial nerves in particular, are
involved. The Broca’s area in the frontal lobe and the temporal lobe in which the primary
auditory area and Wernicke’s area are found, are responsible for hearing and
understanding of speech, respectively. This means that the seven pairs out the twelve
pairs of the cranial nerves together with billions of cells are involved in speech
production.
Figure 1.1 – The speech and language areas of the brain
(Adapted from Gleason, J. B. (1989). The development of language. Columbus: Merrill Publishing Company
p.15);Saladin,K.S.and Porth,M.C . (1998),p.258).
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The human vocal system
The human vocal system is like a musical instrument.
The human vocal system is like a musical instrument. A musical instrument by definition
requires:
- A power source
- A vibrator
- A resonator
- It may or may not have an articulator. Articulation means, “meeting” or
“joining”. Articulation means contact point. This means that two or more
organs can meet to produce a function. Examples of the musical
instrument are the guitar and percussion band.
The human vocal system comprises the organs used to produce speech. This
system consists of the parts of the brain meant for speech production, the voice
box (larynx), the lungs, and the cavities of the nose, mouth, and throat ( pharynx ).
The hearing system complements the speech organs since auditory feedback plays
a major role in listening, self-correction and comprehension.
Some of the human speech apparatus such as, the lungs, larynx, pharynx, oral cavity,
nasal cavity, and jaws; lips, facial muscles, are shown in Figure 1.
- The power source of the human vocal system is the thoracic cavity.
- Vibrator is the vocal folds in the larynx (the larynx is the principal
structure for producing a vibrating air stream).
The resonators are the:
- Oral cavity
- Nasal cavity
- Pharyngeal cavity
These cavities form the collective name called the” vocal tract”. The vocal tract is the
organ for resonance. Resonance is a natural phenomenon whereby there is a sympathetic
vibration causing a marked increase in intensity. Initially, there is a source of vibration
and the frequency of that vibrator matches closely with another. When there is a
vibration, the second vibrator catches up with other because the frequency is closely
related with the other to cause a marked reinforcement of the vibration. The second
vibrator reinforces the vibration and there is an increase in intensity. This is because the
first vibrator modified and intensified the sound it has initiated.
The articulators are either mobile or immobile. The mobile articulators are the lower jaw,
the tongue and lips. The lower jaw tends to move with the tongue and lower lip. The
lower lips in most people move more than the upper lips (Shriberg and Kent 1982, p. 30).
Other mobile articulators are the uvula, and velum (soft palate).
The immobile articulators are the teeth, alveolar ridge and the hard palate (See Figure 1
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Figure 1.2-The schematic diagram of the human vocal system
(a) The Guitar
- Its power source is the fingers that strike the strings.
- The vibrator is the strings, which are manipulated by the fingers.
- The resonator is the cavity. The shape of the cavity modifies the
quality of sound as well as the lengthening and shortening of the
strings by the fingers that manipulate them.
- The guitar has no articulator but the manipulations of the strings
have effect on the output of the sounds or melody produced.
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Tuners
Strings
Wooden box
Figure 1.3 – Acoustic guitar
(b)
-
The Percussion Instrument (band)
Its power source is the hand held drum sticks, which give the band a stroke
- The vibrator is the skin
- The resonator is the box cavity at the bottom that will shape or
amplify the sound.
- The percussion band has no articulator, except that the drum sticks
on the skin articulate to create the strokes.
Figure 1.4 – A percussion band
QUESTIONS
 What is the human vocal system?
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




How will you compare the function of the human vocal system with a
musical instrument?
What are mobile articulators?
Summarize the chapter in your own words.
Draw the human vocal system and label the parts.
If there are two jars with a natural frequency of 1000Hz., 550Hz. and 750Hz.,
respectively, and there is another vibrator, the tuning fork, that has a frequency of
700Hz., which of the jars will match with the tuning fork and why? Explain.

What will be the outcome?
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PART TWO
BASIC INFORMATION ON ANATOMY AND
SPEECH MECHANISM
This chapter gives attention to vocabulary expressions which readers must be familiars
with for a free flow of thought. These terms are expressed below:
Speech:
Any aspect of oral communication including covert thinking processes of language and
overt phonetic processes of speaking ( Perkins, 1977).Speech is a motoric
activity whereby ideas are expressed with meaning orally. It is human specific. It is a
vocal activity which consists of vocal symbols of a given language.
Anatomy:
Framework/Structure of an organism (eg. Human Organs).
Physiology:
Function of such organ(s)
Vibrator:
Any object that is caused to move quickly and continually backwards and forwards.A
vibrator is anything in nature which can move to and fro when a pressure is exerted on it.
This motion displaces the particles and there is forward movement and backward
movement till the vibrator moves back to its resting point. This movement or activity
goes on in 360 degrees making a complete cycle per second measured in the unit of Hertz
(Hz.).
Fundamental Frequency (ƒo):
This is the lowest vibration produced at the laryngeal level and it is caught up by the
vocal tract which is the collective name for the oral cavity, the pharyngeal cavity and the
nasal cavity.
Resonator:
Is anything in nature that has a vibrating property (eg. solid, liquid) that vibrates at its
own natural frequency. Size, shape and texture influence the sort of resonance a sound
should have.
It is a natural phenomenon which involves a sympathetic vibration such that when there
is a source of vibration and the frequency of that vibrator matches closely with another,
there is a marked reinforcement of the vibration. This means that the vibration increases
in intensity. If for instance, a tuning fork produces a pure tone of 440 Hz and if there
should be three jars having different frequencies, the jar that matches closely with the
frequency of the tuning fork, will catch up with this initial sound and will modify and
amplify it. Why? It is because the frequencies of the two vibrators have the same number
of cycles per second.
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smallest jar
produces
natural
frequency
of 1000 Hz.
medium
jar
produces
natural
Frequency of 750 Hz
largest jar
produces
natural
frequency of
440 Hz.
The largest jar with a frequency of 440Hz will catch up wit the tuning fork which also
makes 440cycles per second. Resource therefore is a process whereby the initiate sound
or fundamental frequency (ƒ o) is modified and amplified by a cavity whose frequency
corresponds with that of the initiated sound. Like wise, the human vocal folds initiate the
sound (ƒo) at the larynx level, and the resonating cavities/vocal tract picks it to modify
and amplify.
QUESTION:
Which of these jars will respond favorably to the tuning fork if it is struck and it begins to
make sound and it is held by its stem and placed near the neck of the jar?
ANSWER:
The Largest jar will respond with marked difference in the tone (i.e. increase in tone).
WHY? Because the largest jar has the same natural frequency as the tuning fork.
BASIC CONCEPTS ABOUT THE ACOUSTIC CAVITIES
(RESONATING CAVITIES)
There is basic information on resonating cavities which influence the amplification of
sounds.
a) The larger the opening, the high the frequency
b) The smaller the opening, the low the frequency
c) The larger the cavity, the low the frequency
d) The smaller the cavity, the high the frequency
e) The harder the walls, the high the frequency
f) The softer the walls, the low the frequency
Besides, the different resonances bring about pitch variations.
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Frequency:
The number of times a vibrating object is able to make one complete cycle per second.
This is measured in the unit called Hertz symbolized as (Hz). A cycle is a
motion/activating made within 360°. In speech production, frequency is the rate of glottal
vibration of the glottal space between the vocal folds in a given time period.
It is also established that the lengths of vocal folds influence the sort of frequencies
produced therefore, just as how the long native drum, the” fontomfrom”- the big drum
produces low frequency and the “apentin” also the high frequency, so is it with the vocal
drum.
a) Long vocal folds produce low frequency.
b) Short vocal folds produce high frequency.
c) Tense vocal folds produce high frequency.
d) Relaxed vocal folds also produce low frequency.
Fundamental Frequency (ƒo):
Fundamental frequency of the voice means the lowest vibration or voice. It is the rate of
vocal fold vibration at its lowest tone. Fundamental frequency is symbolized as ƒ o.
The rate of vocal folds vibration or the number of opening and closing cycles in a unit of
time is as the following: 


Adult male has the fundamental frequency of 125 cycles per second or 125Hz.
Adult female has ƒo as 250 Hz.
A newborn baby has ƒo as 500 Hz.
Age and Sex differences in the laryngeal growth:
During the first year of life, the vocal folds almost double in length.
During childhood, the vocal folds growth is gradual.
At the end of first year the vocal fold is about 5.5mm long. At the end of the 5th year,
the vocal folds grow 7.5mm in length. At the end of the 6th year, the length is 8.00mm.
By the 15th year, the vocal folds are about 9.5mm.
Post Pubertal:
Vocal folds reach 17-24mm for Male, but the female it is between 12.5-17mm in length.
During the puberty period, in male the vocal folds grow about 10mm in a very short
period of time. The folds thicken and the lower range of the voice drops about a full
octave. This change in the larynx is known as mutation.
In the female, during puberty, the vocal folds grow in length by about 4mm. The
lower range of the voice drops by about 2 or 3 musical tones. From the above, it can then
be deduced that the male sex has longer vocal folds that vibrate at slower average rate.
However, prior to the onset of puberty there is very little difference in the pitch or pitch
range between boys and girls. Variations of the rate of vibrations of low ƒo are associated
with low pitch.
During ordinary conversational speech, a talker’s ƒo changes almost continuously. Such
changes underlie what is called intonation.
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Pitch:
Pitch is a perceptual attribute of sound. It is that attribute of auditory sensation in terms of
which sounds may be placed on a scale extending from low to high. For instance, a man’s
voice sounds lower in pitch than a woman’s or a child’s because his vocal folds are
longer and vibrate at a slower average rate.
QUESTIONS/ACTIVITY
 Why should short vocal folds generate high pitch sounds?
 Explain the basic concepts of acoustic cavities?
 The fundamental frequencies of the various age ranges of humans differ. Why?
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PART THREE
SPEECH ORGANS
Introduction
Part Two deals with the respiratory system alone and how it functions in terms of its
function related to the organs pertaining to speech production. However, the speech
organs consist of three major systems. These functional systems involved in speech
production are: 1. Respiratory System
2. Laryngeal System
3. Supralaryngeal System
The three systems work in a functional unity to produce a goal, which is meaningful
speech or the spoken language.
These three in analog are related to the Power Source, Vibrator and Resonators plus
articulators respectively as the following: 1. Respiratory System – Power Source
2. Laryngeal System – Vibrator
3. Supralaryngeal System – Resonators plus articulators
The Respiratory System
Respiration is the breathing in and out of the organism. It is the exchange of air between
the organism and its environment in order for it to survive.
The respiratory system consists primarily of the lungs, a rib cage, the abdomen and
associated muscles namely, the scalenes, the pectoralis minor, in extreme cases the
sternocleidomastoid, the diaphragm and the intercostals muscles (external intercostals
and internal intercostals muscles). Other respiratory processes related to respiratory
system are the respiratory and inspiratory cycles, pressures and volumes of air. The
respiratory system is responsible for both regressive and ingressive sound production.
(a) The Rib Cage/Thoracic cage
It is the skeletal framework of the thorax. The thoracic cage has a narrow superior apex
and broad base. The upper limit of the rib cage is formed posterior by the shoulder blades
or scapulae. The rib cage forms a conical enclosure for the lungs, heart and provides
attachment for the pectoral girdle and upper extremity. The pectoral girdle consists of the
clavicle and scapula.
The rib cage consists of 12 pairs of ribs and muscles. Each is attached to the
posterior end of the spinal column. The 12 pairs of ribs have anterior attachment to the
sternum (breast bone) with two floating. Ribs 1-7 have a strip of hyaline cartilage called
the costal cartilage. This extends from the anterior (distal) of ribs 1-7 to the sternum. Ribs
1-7 are called true ribs. Ribs 8-10 are attached to the costal cartilage of rib 7. Ribs 11-12
do not have attachment to anything at the distal end however, both are embedded in the
thoracic muscles. Ribs 8-12 are therefore called false ribs. Ribs 11-12 are called floating
ribs since they lack sternal attachment.
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The spinal column
The spinal column or the vertebral also known as the backbone is made up of a chain of
33 vertebrae with intervetebrae disc. The spinal column supports the skull and trunk. It
allows for movement, protects the spinal cord and serves as a cushioning effect for
stresses produced by lifting, running and walking.
Figure 3.1 – The rib cage (the anterior view)
(Saladin, K. S and Porth,R .N.. 1998 – p. 274)
(b) The Lungs:
The lungs are two irregularly cone shaped structures composed of spongy, porous but
highly elastic material, which contain but a few smooth muscle fibre. They are located
in the thoracic cavity and largely occupy it. The base of the lungs rests on the diaphragm
with the peak reaching toward that of the base of the neck. The paired lungs are not
exactly the same in size, shape, capacity or weight.
The Right Lung
The Right Lung is larger, shorter and broader. Why? This is due to the liver occupying
the upper right abdominal cavity. This causes the diaphragm to be higher on that side
therefore accounts to its shortness. The right lung has three lobes divided by two
fissures. A fissure is a cleft or split. A lobe is a round portion of an organ defined by
fissures and constriction. The three lobes of the right lung are superior, middle, and
inferior lobes (Figure 3.2).
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Left lung
This is longer but smaller. Why? Because the heart occupies much of the left side of the
thorax and this accounts for the smaller left lung. An oblique fissure into superior and
inferior lobes divides the left lung. It has no middle lobe. Each lung has an apex and a
base. The base is broad and concaves and conforms to the thoracic surface of the
diaphragm (See Fig. 3.2). The last cartilage of the trachea bifurcates (i.e., divides into the
right bronchus and left bronchus).The two branches are called ‘bronchi’. The right
bronchus is larger because it supplies the larger lung. ‘Bronchioles’ are smaller divisions
of the branch that are 1mm or less in diameter. Repeated divisions of the bronchioles
ultimately give rise to terminal bronchioles which communicate directly with the alveolar
ducts which in turn open into the minute sacs of the lungs. These are also called the
alveolar sacs or ducts. The ‘Alveolar ducts’ are small hollows pits. The functions of the
alveoli or the entire respiratory system are to bring air close enough to the blood for
oxygen to get into the blood and carbon dioxide to get out it. The interchange of oxygen
and carbon dioxide takes place through these walls of the alveoli. The capillaries, which
are surrounding the alveoli, carry the blood (Anthony, 1968: 101). In the lungs, the red
blood cells exchange their carbon dioxide for oxygen.
The egressive air comes out from the lungs to be used for speech production.
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Figure 3.2 -The lobes of the lungs
(Source:-Zemlin,1981 p.49; & Saladin, K. S. 1998, p. 803).
Respiratory musculature supporting speech
(c) The Abdominal Muscles
Abdominal muscles are four pairs of sheet like muscles, which support the viscera or the
large organs inside the body and special column during lifting, respiration, defecation,
urination, vomiting and childbirth. This sheet- like muscles are: the rectus abdominis,
external oblique, internal oblique and transverses abdominis. The rectus abodominis is a
medial strap like (straight) muscle extending vertically from the pubis to the sternum. The
rectus abodominis is enclosed in a sleeve of fibrous connective tissue called the rectus
sheath. A vertical fibrous strip known as linea alba separates the right and left rectus
muscles. (Linea means, “line”; alba means” white”).
(d) Associated Muscles
The associated muscles are the intercostals muscles. The intercostal muscles of the ribs
are made up of the external and internal intercostal muscles, which contract when we
breathe in to create more vacuum or increase the volume and simultaneously decrease the
pressure of the chest or thoracic cavity.
Actions of External and internal intercostals muscles
The External Intercostal helps in clavicular breathing but plays a passive role. However,
during the intercostals - diaphragmatic breathing, the external intercostals muscle is very
active. This is a preferential breathing for phonation. Why? This is because more space is
vertically provided for more air to fill the space during inhalation. This amount of air
enables fluent, rhythmic and audible speech to be produced.
Saladin and Mattson (1998) describe the External Intercostals action as follows:
When rib l is fixed by scalene, external intercostals draw ribs 2 – 12 upward and outward
to expand thoracic cavity.
The external intercostals muscles extend obliquely downward and interiorly from each
rib to below it. When the scalene muscles fix the first rib the external intercostals lift the
others. Each rib is pulled up somewhat like a handle of bucket, which pulls the ribs closer
together and draws the entire ribs upward and outward. Thus, the thoracic cage enlarges,
to promote inhalation (p.342).
Internal Intercostals
When quadratus lumborum and other muscles fix rib 12, internal intercostals draw the
ribs downward and inward to compress thoracic cavity and cause forced expiration not
needed for relaxed expiration (Saladin and Mattson, 1998).
During inspiration, air is drawn into the lungs due to the muscle contractions to increase
volume for the thoracic cavity. This air is then released to the larynx and supralaryngeal
system for the purpose of speech. The larynx is described as the organ for generation air
for speech production. When special emphasis or loudness is required, the respiratory
system provides more energy by a forceful squeezing of the thoracic cavity. The external
intercostals muscles help the diaphragm to create more vertical diameter for bigger
vacuum to be created for more air to flow in for speech production and respiration
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All normal speech is produced on outgoing breath stream (egressive air flow). As we
breathe out we can use this column to generate sound. In the normal course of expiration
air that comes from the lungs moves (upward through the bronchial tubes, trachea
(windpipe), larynx and pharynx and may leave the body through either the nasal or oral
cavity.
Figure3.3 – The Intercostals Muscles and the diaphragm
(Saladin, K. S. & Porth, C. M.1998, p. 343)
(e) The Diaphragm
The diaphragm, means muscular ‘partition or ‘barrier’ It divides the thorax and the
abdomen. It is dome shaped upward. It is slightly higher on the right side than on the left
due to the position of the heart. It resembles an inverted bowl. It has muscles at its
periphery but a central tendon or a connective tissue within it. The central tendon is
within the diaphragm. A ‘tendon’ is a non elastic band that can always be associated with
a muscle. It is a connective tissue that connects or binds a structure, such as, the
attachment of muscle to the bone or muscle to muscle. The diaphragm has openings that
allow the esophagus and major blood vessels to pass through it.
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Action of the diaphragm
The contraction of the diaphragm makes it flattens slightly and pulls the central tendon
downward and forward, thus increasing the vertical diameter of the thorax. This action
results in an increase in the volume of the thoracic cage and raises the pressure in the
abdominal cavity (Saladin and Porth (1998:342). The diaphragm is considered to be the
most important muscle in breathing.
Expiratory cycle
The lung volume is reduced as air is flowing out of the lungs through the mouth and nose
always.
Principal thoracic muscles during exhalation
1.
Internal intercostals
2.
The subcostals
3.
Transverse thoracic
lying below external intercostals they
all work to pull the ribcage downward
-
Abdominal muscles during exhalation are:
1.
Transverse abdominal
2.
The internal oblique
3.
The external oblique
4.
The rectus abdominals
All function to compress the
abdomen and also help in
forced expiration by pushing
the viscera up against the
diaphragm.
The transverse abdominal is the deepest of all the three abdominal muscles, which
horizontally run across the abdomen.
The external oblique is the most superficial muscle of the lateral abdominal wall. It
runs anteriorly and downward. The internal oblique runs deep to the external oblique.
It runs anteriorly and upward.
The rectus abdominis is a strap like muscle, which runs medially and extends
vertically from the pubis to the sternum. The rectus is enclosed in a connective tissue
which is known as rectus sheath. The left and right muscles are separated by a vertical
fibrous strip called the linea alba (See Figure 2.3).
Muscles that assist in inspiration
These are the following:
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-
External Intercostals muscle-during inhalation directly controls the ribcage
movement.
serratus posterior superior at the back
latissimus dorsi at the back
levatores costarum in the back
sternocleidomastoid
scalenus in the neck
major & minor pectorals
anterior serratus
subclavius
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Figure 3.4 – Major back muscles for inspiration
Figure 3.5 – Thoracic and abdominal muscles for respiration
Overview of breathing for life support
Lung volumes and capacities
Speech production organs hinge solely on a power source to function hence the need to
understand quantity of volumes of air operating in the lungs.
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Tidal volume: The volume of air inhaled and exhaled during any single respiratory cycle,
that is, an inhalation and exhalation is called the tidal volume. The tidal volume for the
young adult males at rest is 750 cu cm. When the young adult males are engaged in light
work, the tidal volume rises to an average of 1670 cu cm. During heavy work the tidal
volumes average 2030cu cm. This means that the intensity of work demands increase in
oxygen uptake so that the value of tidal volume also increases. The mean tidal volume in
general for both adult females and males is 500 cu cm with a minute volume of about 6
litres (Zemlin, 1981). However, 95% range for adult male tidal volume ranges between
675 to 895 cu cm; 95% range of the adult females is between285 to 393 cu cm with a
mean of 339.
Inspiratory Reserve Volume (IRV)
The quantity of air taken in which is beyond that of the tidal volume is the Inspiratory
Reserve Volume. This reserve volume in a state of rest varies anywhere from 1500 to about
2500cu cm.
Respiratory Reserve Volume (ERV)
This is the amount of air, which can be forcibly exhaled following a quiet or passive
exhalation. This expiratory reserve volume usually amounts to 1500 cu cm to about 2000
cu cm in young adults.
Vital Capacity (VC)
The sum of tidal volume, inspiratory reserve and expiratory reserve volumes, which
represent the quantity of air exhaled after deep inhalations, is known as vital capacity.
The quantity of vital capacity in the adult males ranges from 3500 cu cm to 5000 cu cm.
The maximum volume of air that may be exhaled following maximum inspiration ranges
between 3 – 5 litres. Young male adults have a vital capacity of about 4.6 litres and
females have 3.1 litres (Zemlin, 1981, p.93).
The volume of air in the lungs depends on strength of the respiratory musculature and
disease; body size and build; position of the body. Respiratory capacities vary with posture
and body size with a typical total lung capacity in the male adult being 5 – 7 litres. When
lying down, as a result of the abdominal viscera pressing upward against the diaphragm,
and because the pulmonary blood volume increase, the volume and capacities of air
decrease. The value of vital capacity may vary considerably due to body build and the
amount or exercise or heavy-duty work. An athlete’s vital capacity is 6 or7 litres. This is
30 – 40 percent above normal. For strenuous exercises, such as pushing, lifting, etc, more
air is needed. At quiet breathing, and at rest, air is exchanged about twelve times a minute.
At rest both females and males have no significance difference in breathing rate but during
heavy work, the rate is increased to 26 breaths per minute for males and 30 breaths per
minute for females. At normal quiet breathing approximately 0.5 litres is inspired and
expired at each breath (Zemlin, 1981).
Overview of breathing for speech production
Respiration and speech production
The goldsmith to produce air for his fire chamber in his workshop with a bellow, can be
likened to the processes involved in respiration with regard to speech production.. The
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vacuum or space within the bellow represents the thoracic cavity. Before the bellow can
rise to the top level, more air is drawn into the bellow that is the ingressive airflow. The
same is the breathing in of air into the lungs for sound production through the respiratory
passage comprising the oral, nasal, pharyngeal and laryngeal cavities. In the
case of the bellow, it has only one passage or outlet for air taking since it produces
uniform air. However, in human, the various cavities help in variation of sounds, for
example, for resonance, of /m, n, ŋ / speech sounds, the air are routed through the nasal
cavity for adequate resonance.
The respiratory cycle functions by replenishing oxygen in and removing unwanted
carbon dioxide from the blood.
The respiratory system consists primarily of lungs, rib cage, abdomen and associated
muscles, are responsible for both aggressive and ingressive sound production. During
inspiration, air is drawn into the lungs due to muscle contraction to increase volume for
thoracic or chest cavity. This air is then released to the larynx and supralaryngeal system
for purpose of speech. When special emphasis or loudness is required, the respiratory
system provides more energy by a forceful squeezing of the thoracic cavity.
Summary of the Respiratory System in terms of its Role in
Speech Production:
The Respiration system provides the motive force for speech.
During inspiration, air is drawn into the lungs as the result of muscle contractions that
increase:
 The volume of the thoracic or chest cavity.
 The muscles of the respiratory system release air into the larynx and
supralaryngeal system for the purpose of generating speech (egressive and
ingressive speech sounds).
 When emphasis or loudness is required the respiratory muscles can act by forceful
squeezing of the thoracic cavity.
 The respiratory passage is: the nasal cavity, oral cavity, pharyngeal cavity, larynx,
trachea and bronchi that lead to the lungs where there is exchange of gas.
QUESTIONS:
 Explain the Respiratory System.
 Which of the types of respiration will you like to be used in speech
production? Explain.
 Explain the role of the Tidal Volumes during work.
 What is the Vital Capacity?
 List the abdominal muscles for breathing and speech production.
 Summarize the chapter in your own words.
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PART FOUR
THE LARYNGEAL SYSTEM
Introduction
The laryngeal system comprises the larynx which is also the voice box, the vocal folds
the ligaments and membranes. The vocal folds being about ¾ inch (17mm) long in adult
male and shorter in children and in women vibrate when they come together. In man, the
ƒo is 125Hz and 250Hz in women with about 500Hz in newborn baby. During speech,
the different ƒo changes give the intonation. The sound wave from the larynx is made
into speech by the supralaryngeal system, which includes the cavities and the articulators.
The laryngeal system is very important for speech production. It comprises:
(a) the larynx which encloses the vocal folds
(b) the ligaments
(c) the membranes
(d) the laryngeal muscles
Position: It is situated between the trachea (wind pipe) and pharynx. It forms the
superior terminal of the trachea. It is unpaired and found at the midline and located in the
anterior neck region. It is composed of cartilages and muscles. The larynx is the
principal structure for producing a vibrating air streams. The vocal folds are part of the
larynx and constitute the vibrating elements vibrating. The larynx is regarded as an
intrinsic component of the respiratory system.
Functions of the larynx:
1. The larynx serves as a protective device for the lower respiratory tract;
2. It prevents foreign bodies such as, food participles from entering the larynx;
3. It expels foreign substances from entering
4. It prevents air from escaping the lungs.
(A) The Supportive Framework: The Hyoid Bone
Figure 4.1 – Lateral view of the hyoid bone
-
The hyoid bone is not an integral part of laryngeal framework
however; it gives support to the larynx.
21
-
The hyoid bone is a U-shaped bone which is unique. It is found at
the superior part of the larynx.
- It is unique since it is not directly attached to any other bone in the
skeleton.
- It is bound in position by muscles and a ligament therefore it is
highly a mobile structure.
Muscles that approach the hyoid bone are the following:- Tongue muscles, chin, muscles and ligaments from the temporal
bone approach from below and in front. Extrinsic muscles from the
larynx approach the hyoid bone from below.
Others such as muscles from the sternum (breast bone) and clavicle (collar bone) muscles
approach the hyoid from below:
Function: Hyoid bone is a supportive structure for the root of the tongue. Why?
(1)
The hyoid bone forms the inferior attachment for the bulk of the tongue
muscles.
(2)
The larynx is suspended some what from the hyoid bone
(3)
The hyoid bone serves as a point of attachment for some extrinsic laryngeal
muscles.
The Extrinsic Laryngeal Muscles
The primary function is to (1) Support the larynx (2) Fix the larynx in position.
The extrinsic laryngeal muscles are as follows:
1)
The digastric muscle
2)
The stylohyoid muscle
3)
The geniohyoid muscle (chin plus hyoid)
4)
The mylohyoid muscle (mill plus hyoid) (this is the floor of the mouth
muscle).
5)
The omohyoid muscle
6)
The sternothyroid muscle
7)
The thyrohyoid.
Figure 4.3 shows the diagram on the extrinsic laryngeal muscle. Except for digastric
muscles and mylohyoid muscles, all the muscles are collectively known as the ‘strap
muscles’ of the neck (See Fig. 4.4)
22
Figure 4.2 Extrinsic Muscles (Saunders W. H. 1964, plate IV)
The posterior digastric muscle originates from the mastoid process and inserts into the
hyoid bone. It contracts to draw the hyoid bone up and backwards.
The stylohyoid originates from the styloid process and inserts into the hyoid bone. The
contraction of this bone draws the hyoid bone up and backward.
- The Geniohyoid muscle takes its origin from the mandible (the lower
jaw) and inserts into the hyoid bone. (Note the geniohyoid is a
paired cylindrical muscle located superiorly to the mylohyoid
muscle). It helps to pull the hyoid-bone up and forward.
- The Omohyoid muscle originates from the superior border of scapula
(shoulder blade) and inserts into the hyoid bone (Note: ‘Omo’ – is a
Greek work meaning ‘shoulder’). The omohyoid muscle depresses
the hyoid bone.
- The sternothyroid muscle originates from the manubrium sterni
(body of the sternum) and inserts into the thyroid cartilage. It is a
long slender muscle located in the anterior neck. Its principal work
is to draw the thyroid cartilage downward.
- The thyrohyoid takes its origin from the thyroid cartilage and inserts
into the hyoid bone. This muscle depresses the hyoid bone. It also,
elevates the thyroid cartilage when the hyoid is fixed.
- The mylohyoid means the floor of the mouth or the mill, plus hyoid.
The mylohyoid is thin and trough like sheet of muscle. It arises from
23
-
the mylohyoid line which is a well defined bony ridge and attaches
itself to the hyoid bone.
It helps in depressing the mandible and swallowing (deglutition).
The Supra Hyoid muscles that are Elevators are
1.
mylohyoid
2.
geniohyoid
3.
digastric
4.
hyoglossus
5.
stylohyoid
The Infrahyoid Depressors are:
(1) Sternohyoid
(2) Omohyoid.
These muscles draw the hyoid bone downward.
Is it necessary to include the hyoid bone in phonation (i.e. Speech Production)?
Because about 30 muscles either take their origin form or insert into the hyoid bone,
many of these muscles are essential for speech production, some of which are mentioned
as above.
The larynx is suspended somewhat from the hyoid bone (i.e. the hyoid bone
serves as superior attachment for some extrinsic laryngeal muscles).
Summary:
The hyoid bone serves as a supportive framework for the laryngeal system.
- This bone is unique in the body and has no attachment to any other
bone.
- Most muscles necessary for phonation take their origin from it and
insert in it. Due to those extrinsic muscles necessary for speech
production which attach to the hyoid bone, it can be concluded that it
supports the larynx and enables speech production to be made.
QUESTION/ASSIGNMENT:
 Describe the Hyoid Bone
 Why is the hyoid bone so necessary or what roles does it play? Which muscles
attach to the hyoid bone?
(b) The cartilaginous Framework of the Larynx
The Larynx:
The structure or framework of the larynx consists of 9 cartilages and their connecting
membranes and ligaments.
(See Fig. 4 and 5).
These 9 cartilages are:(1) Thyroid
(2) Cricoid
(3) Epiglottis
-
1
1
1
24
(4) Arytenoids 2
(5) Corniculate 2
(6) Cuneiform 2
- The Epiglottis, the corniculate and cuneiform are Elastic Cartilages.
They are somewhat yellow and opaque.
- The Thyroid, Cricoid and Arytenoids are composed of the hyaline
cartilage. These cartilages appear to be bluish-white and translucent.
Hyaline cartilages are found in joints also.
Figure 4.3: The cartilaginous framework of the larynx
(Ref: Zemlin (1981) page 138; Clinical Symposia, 1964, vol.16no.3 p.70)
25
Figure 4.4: Ligaments and membranes of the larynx
(Saunders W. H. 1964, plate IV).
26
(1).The thyroid Cartilage:
- It is the largest cartilage which is composed of 2 quadrilateral plates
called the Thyroid Laminae.
- Both plates fuse together to make a prominent V shaped notch called
the Superior Thyroid Notch.
- The anterior projection of the larynx is called the Thyroid or
laryngeal prominence or Adam’s apple.
- The thyroid cartilage is mainly hyaline cartilage which is flexible
and appears as a bluish white translucent substance.
(2).
The cricoid Cartilage:
This is ring like. It is located immediately above the uppermost tracheal ring. It is
smaller but stouter than the thyroid and forms the lower portion of the laryngeal frame
work.
Function:
The cricoid and thyroid articulate or meet each other laterally hence they
have formed a joint which permits either the thyroid or cricoid to rotate. This joint is the
Cricothyroid joint. The rotation of this joint creates a pitch change during voice
production.
(3) Epiglottis
-
The Epiglottis (“epi” – ‘means upon; “glottis” means the space
between the vocal folds. Epiglottis therefore means upon the glottis).
The epiglottis is leaf- like in structure and it is composed of an
elastic cartilage.
Position:
(a)
(b)
The epiglottis is located just behind the hyoid bone and by the root of
the tongue.
The broadest part of this leaf-like structure is fastened to the hyoid
bone by a ligament known as the hyoepiglottic ligament.
Function:
The epiglottis serves as a protective device. This means that it prevents food from
entering the larynx during swallowing (or deglutition).
(4)
The Arytenoids Cartilage:
It is mainly hyaline cartilage. This is a paired cartilage. Each resembles a three sided
pyramid. It has a pointed projection known as the vocal process at the anterior angle near
the base.
27
Figure 4.5 Pointed projection of the Arytenoid Cartilage
This muscular process articulates with the cricoid cartilage. It is a point of attachment for
the Lateral and Posterior Cricoarytenoid muscles.
-
At the apexes (tips of the Arytenoid cartilages are capped by a pair
of cone shaped elastic cartilage called the Corniculate Cartilage.
(4)
Corniculate Cartilages
These are paired conically shaped elastic cartilages which have large numbers of the
elastic fibres. They appear to be some what yellow and opaque. Other examples of the
elastic cartilages are found in the ear, and the external auditory meatus. The corniculate
cartilages are found at the apexes of the arytenoids cartilages.
Function:
They give protective function.
(5)
Cuneiform Cartilages:
- It is a paired elastic cartilage, lateral to the Corniculate Cartilage.
- They are embedded in the aryepiglottic folds and covered by a
connective tissue fat and mucous membrane.
- The aryepiglottic folds are found by the lateral marginal portions of
the epiglottis.
28
-
The cuneiforms cartilages support the aryepiglottic folds by
stiffening them to help maintain the opening to the larynx.
Biological functions of the larynx:
The larynx functions as a protective Device for the lower respiratory tract.
(1)
It prevents air from escaping the lungs. This facilitates those activities
that demand high elevated abdominal pressures such as forced bowels,
bladder evacuation and heavy lifting.
(2)
It prevents foreign substances from entering the larynx during
breathing. Also it prevents fluids we swallow into the esophagus
during eating.
(3)
It forcefully expels foreign substances which threaten to enter either
the larynx or trachea.
The threatening substances and foreign bodies are prevented from entering the larynx by
the active closure of the laryngeal valve.
Non-biological Function of the larynx: (The Vocal folds)
The larynx non-biological function of the larynx is sound production. The vocal folds
which are enclosed in the larynx are descriptive names. They are also described as
‘Vocal bands’ or vocal cords’. The folds are mainly consisting of a bundle of muscles
called thyroarytenoid.
- The vocal folds are shorter in children and in women than in the
adult male.
- They are 17mm-24mm or about 3 inches long in the adult male. The
vocal folds are 12.5-17mm in the adult female and about 3mm in
length in the infant. In children, by the end of the first year, it is
5.5mm long. At the end of the 5th year, the vocal folds grow 7.5 in
length. By the end of the 6th year, it is 8.00mm long. At around the
puberty age level, which is about the age of 15 years, the vocal folds
are 9.5mm long.
The growth of the vocal folds in male at Puberty Period
There is a spurt in growth of the vocal folds within a short period. In the male the vocal
folds grow about 10 mm. in a very short period of time. They thicken and the lower range
of the voice drops about a full octave. This change in the larynx is known as mutation.
The growth of vocal folds in female at Puberty Period
In the female during puberty period the vocal folds grow in length by about 4mm. and the
lower range of the voice drops by about 2 or 3 musical tones.There is a clear distinction
that the vocal folds of male are normally longer than that of the female. Prior to the onset
of puberty, there is very little difference in the pitch range between boys and girls. The
variations in the length of the vocal folds bring about pitch changes.
Longer vocal folds will vibrate at a slower rate therefore the pitch will be low. Therefore
in adult male the rate of vibration per second that is the ƒo is 125 Hertz. Shorter vocal
folds will vibrate at faster rate. As a result ,the pitch of the fundamental frequency (ƒo) of
29
the adult female which is 250 Hertz and about 500 Hertz in infants or children have
higher pitch respectively than that of the adult male. In an ordinary conversational
speech, a talker’s ƒo changes almost continuously. These changes bring about intonation.
The vocal folds can be lengthened, shortened, tensed, relaxed, abducted and adducted.
These are the various behaviours of the vocal folds which bring about the pitch changes
or the intonational pattenrs of speech.
Intrinsic laryngeal muscles
These are categorized according to the effects they have on the shape of the glottis and on
the vibratory behaviour of the vocal folds.
(a)
The adductor muscles
(b)
Abductor muscles of the larynx (see fig. 3.4)
(c)
The Relaxer Tensor muscles of the larynx.
30
Figure 4.6 Adductors, Abductor and Relaxer Muscles of the Larynx.
(Saunders W. H . 1964, plate IV)
(a) The Adductor Muscles
‘Adduction’ means to be drawn to the midline. In relation to the speech production,
‘adduction’ means that the vocal folds are drawn together to the midline to vibrate for
phonation. The adductor muscles are:1.
Lateral Cricoarytenoid Muscle.
31
2.
Interarytenoid Muscle (This is between the arytenoids and described further
by the position it lies.)
(a)
Transverse Arytenoid Muscle
(b)
Oblique Arytenoid Muscle
Functions
(1)
(2)
On adduction the muscles bring the vocal processes of the
arytenoids cartilages together for phonation for voiced sounds
such as all vowels and all voiced consonants e.g, b, d,g,z,l,m,n,
etc.
They help to protect the larynx from foreign materials. Besides,
the vocal folds can close completely or slightly less than
complete to restrict air flow from the lungs as in heavy lifting,
bowels evacuation etc.
(b) The Abductor Muscles
These are muscles drawn apart as in quiet breathing. As the vocal folds are drawn apart,
a space is created between them. This is called the glottis. There is only one Abductor
Muscle in the larynx. This is the Paired Posterior Cricoarytenoid Muscles. These
muscles are broad and stout and have fan shapes.
(c) The Relaxer Muscle
The Relaxer Muscles are the Lateral Cricoarytenoid and the Thyrovocalis/Vocalis
Muscle. The Thyrovocalis muscle forms part of the Thyroarytenoid muscle which is the
main mass of the vibrating vocal folds. The vocal folds achieve relaxation by the
muscles relaxatory behaviour in form of shortening the vocal folds.
(d) Tensor Muscle
The two main Tensor Muscles are the Cricothyroid and the Thyroarytenoid Muscles.
These muscles elongate and tighten the vocal folds hence cause tension. Such an action
causes pitch changes. This behaviour of the Tensor Muscles complement the function of
the cricothyroid joints in the pitch change of the voice
QUESTIONS:
 Which muscles adduct abduct, relax and tense the vocal folds?
 Which processes are adapted to achieve each of these?
 What is the significance of the behaviour of the vocal folds in (a) adduction?
(b) abducting?
 What positions do the folds take during breathing and in the production of
voiceless sounds?
 What can you say about the variations in pitch changes. (a) What are the
causal factors? (b) Give examples of what happiness before a low pitch is
achieved. Relate you answer to the muscles their behaviour etc.
 Define
mylohyoid
geniohyoid
 Draw the parts of the larynx (label each part)
32
PART FIVE
THE SUPRALARYNGEAL SYSTEM
Supra – is a morpheme that means above. Supralaryngeal System – means the part of the
speech mechanism that lies above the larynx.
The supralaryngeal system consists of the 3 major cavities or chambers as the following
the:
(1a) pharyngeal cavity
(1b) oral cavity
(1c) nasal cavity
Other components of the supralaryngeal system are the:
(2)
Velum and pharyngeal walls
(3)
Lower Jaw/Mandible
(4)
Upper jaw (maxilla)
(5)
Tongue
(6)
Lips
(7)
Teeth
Figure 5.1 Diagram of the supralaryngeal system
33
Figure 5.2-The oral cavity
(Saladin. S. and Porth, C M.;1998)
Pharyngeal Cavity
The pharynx lies directly above the larynx. It is essentially a muscular tube. The
pharynx divides into two other cavities which are the oral (or mouth) and the nasal (or
nose). The sound energy from the larynx travels up through the pharynx and then enters
the oral cavity and the nasal cavity or both. The direction of the sound energy is
determined by the position of the velum or soft palate. This soft palate is an extension of
muscle of the bony hard palate that forms the roof of the mouth.
Functions:
(a)
Then Velum closes the nasal cavity from the pharynx to allow sound to be
directed into the oral cavity.
(b)
When the velum is lowered sound energy may enter the nasal cavity through
the nose.
Examples of words to either enter the nose or mouth or both are the following:
- /man/ (mæn) enters both nose and mouth. Why? Because (m) or (n)
sound energy is nasal consonant sounds therefore, need nasal
resonance. The vowel /a/ needs oral resonance since the egressive air
stream travels by the mouth.
Without nasal passage, the /m/ and /n/ as in /man/ would have
sounded /bad/. This is denalisation. You may hold your nose tightly
and practise it. The same thing happens if one has severe cold,
because of the blockage of the nasal passage.
34
Velopharyngeal sphincter:
The velopharyngeal sphincter refers to the velum and pharyngeal wall velum acts
like a valve by opening or closing the entrance to the nasal cavity.
(a)
During respiration and during the production of nasal sounds, the velum is
lowered.
(b)
The velum is raised when we engage in activities such as sucking and blowing.
The velum helps in the closure of the velopharyngeal port. This is the opening between
the oral-pharyngeal and nasal cavities. The lateral walls of the velopharyngeal port move
inward (inward movements) to assist in closing the port as well. With people who have
short palate or cleft palate. The back wall of the pharynx bulges out to meet the velum to
activate the closure of the velopharyngeal port.
The jaw or mandible
(1)
It contributes to the movement of the tongue and lower lip but its primary
function is to contain the upper jaw. The two processes of the mandible called the
condyle-processes join to the temporal bone by the temporomandibular joint. (The
mandible is a movable bone but face and articulates in the temporal bone (i.e. the
temporal mandibular joint that permits hinge-like movement and gliding action. Here the
jaw inserts into the temporal bone of the skull. However in terms of speech production
the jaw modifies the resonant characteristics of the oral cavity. (i.e.) its movement tends
to cause the tongue and lower lips to move with it. The mandible can elevate or depress
retract or protrude. The jaw movement is slight in speech production but
- Any sluggish movement inappropriate or inadequate movement can
result in sever articulation depicts.
- Any improper articulation between the mandible and temporal bone
(temporomandibular joint) may result in malocclusion (i.e. any
deviation from normal occlusion of the teeth.
Occlusion (i.e. the full meeting of the masticating surfaces of the upper and lower teeth it
involves the alignment or the relationship between the upper dental arch and the lower
dental arch and the positioning of individual teeth.
Depressor muscles of the mandible Arc:
(1)
(2)
(3)
(4)
The digastric muscle
The mylohyoid muscle
The geniohyoid “
The lateral (external) pterygoid found around the condyle of the
mandible
Upon contraction, the hyoid bone is raised up or depresses the mandible.
The Tongue:
The tongue is a muscular organ. It is associated with sensory information about food in
the in the oral cavity. It is also involved in deglution and speech. The tongue is in the
floor of the mouth and it is attached to the hyoid bone and mandible.
35
The extrinsic Muscles of the tongue
The three extrinsic tongue muscles are largely responsible for the movement of tongue
within the oral cavity. These muscles are: the styloglossus muscles, the genioglossus
muscles, and the hyoglossus muscles.
The styloglossus Muscle
The styloglossus muscles come from the styloid process of the temporal bone. It inserts
itself at the lateral border of the tongue.
Action: It elevates the ear of the tongue and retracts protruded tongue. It is innervated by
the Cranial Nerve XII which is the hyoglossus cranial nerve. It acts as an antagonistic
nerve to the genioglossus because it elevates the rear of the tongue.
The genioglossus muscles
This muscle originates from the mental spine on the lingual surface of the mandible. It
inserts into the dorsum (surface of the tongue) and body of the hyoid bone.
Action
The genioglossus muscle retracts, depresses and protrudes the tongue. The cranial nerve
which activates the cranial nerve is CN XII.
The Hyoglossus Muscles
It originates from the greater cornu of the hyoid bone and inserts into the posterior half of
the side of the tongue.
Action
The hyoglossus muscles depress the sides of the tongue and contribute to its retraction.
The Cranial Nerve XII activates it.
Sensory innervation of the tongue
o General sensation of the mucosa of the anterior two-thirds of the tongue is carried
I the lingual nerve, a branch of the mandibular division of the trigeminal nerve
(Cranial Nerve V).
o For special sensation (taste) the anterior two-thirds is supplied through the chorda
tympani nerve, a branch of the facial nerve (Cranial Nerve VII).
o The mucous membrane of the posterior one-third of the tongue is supplied by the
lingual branch of the glossopharyngeal nerve (Cranial Nerve IX) for general and
special (taste) sensation including the circumvallate papillae
36
Figure 5.3 Extrinsic Muscles of the Tongue (Lateral View)
Palmer, J.M. (1972). Anatomy for speech and hearing (2nd ed. )Harper &Row Publisher.
Intrinsic Muscles of the tongue
Intrinsic muscles of the tongue provide changes in the shape of the tongue while the
extrinsic muscles are largely responsible for its movement in the oral cavity.
The intrinsic tongue muscles:
(1) Vertical
(2) Transverse
(3) Inferior Longitudinal
(4)Superior Longitudinal.
Vertical
The vertical tongue muscle is formed at the borders of the tongue. It originates from the
superior surface of the tongue near the tip edges. It inserts into the inferior surface of the
tongue.
Action: It widens and flattens tip. It is innervated by the hypoglossus nerve – Cranial
Nerve XII.
Transverse
It originates from the tongue septum and median portion. It inserts into the mucous
membrane at the sides of the tongue.
Action: It elongates, narrows, thickens tongue and lifts its sides. The transverse tongue is
innervated by Cranial Nerve XII .
Inferior longitudinal
It originates from the hyoid bone, inferior surface of the base of the tongue and inserts
into the tip or the apex of the tongue.
Action: It widens, shortens and pulls the tip downwards.
Superior longitudinal
It originates from the septum of tongue and submucous part near the epiglottis.
37
Action: It widens, thickens and shortens tongue, raises tongue tip and edges; forms a
concave dorsum. It is innervated by Cranial Nerve XII.
The tongue is essential in the production of sounds and in particular in reference to the
vowel production the vowels are described according to tongue height or tongue position,
lip rounding.
Functional Parts
Since the tongue has complicated movements it can be divided into 5 functional parts
(showing its functions,).
(a) The body of the tongue:(bulk or mass of it). The tongue is essential in the production of sounds and in particular in reference to the vowel production the vowels are
described according to tongue height or tongue position, lip rounding.
The vowel production is described with reference to the tongue body. For example, the
Vowel Quadrilateral represents the body of the tongue and various positions of the
Vowels of the English Language or the Cardinal vowels.
eg. The English Vowels in the words:
/heat, hoot, hot, hat/ have tongue body positions (See vowel Quadrilateral – Fig. 5.3).
Front
Central
Back
..Close
i:
u:
i
u
..Half-close
З:
e
..Half-open
Λ
ɔ:
æ
a:
Figure 5.4 -The vowel quadrilateral
The / i / in /heat --- has a tongue position that is high in the front
38
ɔ
..Open
The /u / in /hoot / --- has a tongue position that is high but at the back.
The / ɔ / in /hot / --- has a mid-back opposition of the tongue or hit
The / æ / in /hat / --- has front-low position of the tongue
(b) The tip of the tongue: Is essential for speaking, since some plosives eg./ t ,d /
lateral /1/ at the alveolar ridge, nasal /n /, voiceless fricative / th /, sibilant /s/ the
underlined letters in this sentence are produced with the tip of the tongue making contact
somewhere in the mouth.
(c)The blade of the tongue
The blade is located just behind the tip of tongue.
It is noted for producing /sh/ as in sheep
(d) The dorsum of the tongue (also known as back). It is the posterior surface of the
tongue situated partly in the oral cavity and partly in the oropharynx. It appears velvety or
has the characteristics of roughness. The dorsum is generally convex. It is divided into an
anterior part which faces superiorly and anteriorly and a posterior part. These two parts
are separated by a V–shaped furrow/groove known as the sulcus terminalis the limbs of
which run laterally and forwards on each side from a small pit called the foramen caecum
(this marks the site of the upper end of the thyroid diverticulum). Also present is the
median sulcus which runs along the dorsum. The median starts near the tip of the tongue
and terminates at the foramen caecum. The base of the V points posterior and the sulcus
terminalis serves as the boundary between the oral part or anterior
and the pharyngeal
part or posterior part or posterior .
These two parts differ in the structure of their covering mucosa, in their nerve supply and
their development. Its anterior two-thirds ( ) is roughened and contains papillae. (The
papillae are confined mainly to the anterior
of the tongue that is they are present only
on the upper and lateral lingual surfaces and only on the part of the tongue which is in
front of the tongue which is in front of the sulcus terminalis). This portion is towards the
oral aperture. The roughness results from the elevations or projections of the mucous
membrane above the general level of the lingual surface of the tongue.
Sounds made with the dorsum of tongue are:
/ k / as in key
/ g / as in go
/ θ/
as in thing.
The dorsum makes its articulation with both the soft and hard palate.
(e)
The root of the tongue
The root of the tongue is important in shaping the vocal tract for vowel and consonant
sounds.
39
Figure 5.5 -The tongue
(5)
The Lips
The upper and lower lips primarily contribute by opening and closing as in production of
the word /pop/.
The lips are rounding or protruding as in the vowel /u / as in /you/ .
40
Figure 5.6 – The facial muscles
(Saladin,K. S.and Porth,C. M. (1998 )
Muscles of the face
There are ten muscles that form muscles of the facial expression. These muscles work
together to enable us laugh , smile, and pout the lips as in kissing and singing. Chewing
and shaping the mouth as in pursing or closing and opening the mouth in yawning,
spitting out foreign objects and assisting in keeping bolus of food in the mouth are
examples of vegetative functions. These ten muscles are the following:
(1) Orbicularis oris
(2) Risorius
(3) Canine
(4) Zygomatic major and minor
(5) Quadratus labii inferior
(6) Quadratus labii superior
(7) Triangularis
(8) Mentalis
(9) Buccinator
(10) Platysma
All the muscles are innervated by the cranial nerve seven (CNV11). Others which
complement these muscles are the procerus, frontalis, depressor anguli oris, levator
palpebrae superioris and orbicularis oculis ) (Palmer, 1972:50).
41
Details on the facial muscles lips for expression are below:
Orbicularis oris
It is a sphincter or ring like muscle which closes the mouth and puckers the lipsIs is
innervated by the Cranial Nerve V11.
Risorius
It is the muscle at the angle of the mouth which retracts the corner of the mouth. This
muscle is activated by the Cranial Nerve V11.The Risorius muscle upon contraction
helps to draw the mouth angle laterally as in laughing. In relation to production of sound
/m/, the orbicularis oris – muscle as well as the risorius are used. The risorius together
with the Zygomatic Muscles perform the same activity of smile on the face.
Canine
It is found at the angle of the mouth of the upper lip. It is also known as the levator anguli
oris. It elevates corners of the mouth as in smiling and laughing. The facial nerve (cranial
nerve VII) is responsible for its activity.
Zygomatic
It is at the angle of the mouth of the upper lip. It begins at the zygomatic bone lateral to
the origin of the canine muscle. It draws the corner of the mouth up and backward It is
called the laughing muscle. The Cranial Nerve V11, activates it.
Quadratus labii inferior / The Depressor labii Inferior also known as (quadratus
labii inferior) is located beneath the lower lip just lateral to the mid line muscle or
vertical muscle which is the mentalis. This is the muscle at the angle of the mouth. It
depresses the lower lip. It is activated by the Cranial Nerve V11. Upon contraction, this
muscle draws the mobile lip downward and lateral ward as in phonating as in the word
“tough” / tΛf /; / ai / as in ;/smile/ - [smail].This same muscle helps to express terror or
irony (Palmer,1972 p. 50 ). Try each out and see what happens.
Quadratus Labii Superior/Levator Labii superior /Alaeque Nasi
This is the muscle which originates from the frontal process of the maxilla, the zygomatic
bone and the lower margin orbit and insert in the upper lip at midline.It is the most
median of superior lip muscles. It elevates the upper lip. It is also the muscle for
contempt or disdain. It is also innervated by the Cranial Nerve V11. This muscle is the
proper elevator of the upper lip. In terms of speech production, the upper lip is elevated in
phonating / I /as in /hit/.
Triangularis / depressor angularis oris.
I t is located at the angle of the mouth of the lower lip. This muscle depresses that angle
of the mouth of the lower lip. Together with the zygomatic muscles, smiling is achieved.
Cranial Nerve V11 activates this muscle.
Mentalis muscle
It is close to the midline of the mouth and below it .It is activated by the Cranial Nerve
V11. It acts to pout or protrudes the lower lip; that is, it closes the mouth and puckers
42
lips. It also wrinkles the skin of the chin. It is sometimes considered a major part of the
platysma muscle.
Buccinator
It also found at the angle of the mouth which forms part of the upper and lower lips. It
flattens the cheek. It is the principal muscle of the cheeks. It is activated by Cranial Nerve
V11.
Platysma
It is formed by the muscle bundles found along the sides of the neck. It depresses the
mandible and helps in pouting. It depresses the corner of the neck and wrinkles the skin
of the neck and chin. It is activated by the Cranial Nerve V11.
Teeth
Teeth are a major component of the oral cavity and are essential for the digestive process.
Teeth are embedded in and attached to the mandible and maxillae. Teeth are classified as
incisors, canines, premolars and molars. Primary deciduous/milk teeth appear in the oral
cavity between 5 months and 2 ½ years. The first to erupt are the lower medial incisors
at about 6 months. The lower teeth frequently precede the upper in eruption. The primary
teeth are twenty (20) in number that is five (5) in each of the four quadrants: 2 incisors,
one canine and two premolars.
Each tooth has a crown which projects above the gum (gingiva) and a root (s) which is
buried in the alveolus of the maxillae and mandible.
Each tooth is composed of a specialized sponge tissue known as pulp covered by three
calcified tissues:
1. dentine
2. enamel
3. cementum
Figure 5.7 (a) – Deciduous teeth
(Saladin, K. S. &Porth, C.M.;1998)
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Figure 5.7 (b) – Permanent teeth
The permanent teeth begin to appear in the oral cavity at about 6 years and would have
replaced the primary deciduous teeth by about 12 years. The permanent teeth are 32 (16
permanent teeth in each jaw) i.e. 8 in each quadrant: 2 incisor; one canine; two premolars
and three molars. (This makes a total of 8 incisors, 4 canines, 8 premolars and 12 molars
44
PART SIX
EXERCISES
Label the parts and describe their functions.
Picture 1
Picture 2
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Picture 3
Match the numbers with the appropriate names.
Picture 4
46
Picture 5
Match the numbers with the labels
Picture 6
47
Identify the cranial nerves.
Picture 7
48
REFERENCES
Boison,C. (2000)The effect of poor reading skills on academic performance: Some
observations during 2000 teaching practice. The WEB pp 9-11.
Donani,C.& Avoke M.(1996).Identification of children with learning disabilities in JSS
one ( Winneba Township).Ghanaian Journal of Special Education pp. 64-73 .
Gadagbui,G. Y. (2001). Journal of Educational Development,1 (1),pp. 1-5..
Nicolosi,L. Harryman, E.& Kresheck,J.(1980).Terminology of communication
disorders, speech, language, hearing, London: Williams and Wilkins.
Palmer J.M. (1972). Anatomy for speech and hearing (Second Edition) New York:
Harper and Row.
Parker, A. C. (1968). The respiratory system in structure and function of the body.
St. Louis, The C. V. Mosby Company.
Saladin, K. S., Porth, C. M. (1998). Anatomy and physiology. The unity of form and
function. Boston: McGraw-Hill.
Saunders, W. K. (1964). The larynx. Reprinted from Clinical symposia, 16, 3, plate
I – IV.
Shriberg, L. D & Kent, R. D.(1982). Clinical phonetics. New York:John Wiley and
Sons pp.21 – 33.
Yemeh, P.N.(1997).Using action research to address the problem of poor writing
skills at the junior secondary school: A case study of Advanced Demonstration
Junior Secondary School, Winneba, English Department, UCEW.
W.R. (1981). Speech and hearing science anatomy and physiology.
Cliffs, New Jersey: Prentice-Hall Inc.
49
Englewood
GLOSSARY
Inferior
situated beneath or lower towards the feet
Synonym
caudal
Anterior
toward the front
Posterior
toward the back or away from the Front
Articulation joining/meeting
Articulators those structures responsible for modification of the acoustic
properties of the vocal tract: tongue, lips soft palate, hard plate
and teeth.
Ab
away from
Abduct
to draw away from the midline (drawn apart)
Adduct
move toward the midline (drawn together)
Glottis
the space between the vocal folds
Vocal tract
is a collective name for the oral nasal and pharyngeal
cavities which modify the vibrating air-stream produced by
the vocal folds.
System
when two or more organs join for functional unity
Ligament
to bind. Ligament binds eg. bone to bone or bone to
cartilage
Cartilage
is a connective tissue that is softer and more flexible than
bone (generally firm but has elastic property basically
found in joints)
Supra
above
Infra
below
Omo
pertaining to shoulder
Omohyoid muscle
muscle pertaining to the shoulder and the hyoid bone
Mylohyoid muscle muscle of the floor of the mouth connecting to the hyoid
bone
Sternohyoid muscle muscle connecting the sternum (breast bone to the hyoid)
Geniohyoid muscle muscle from the chin is connecting the hyoid bone
Velopharyngeal sphincter
this is a mass or muscle that determines oral/nasal
air flow by closing (uncoupling) for oral air flow
and coupling for nasal air flow
Naso Pharynx
it is the opening linking the lower end of the nasal cavity
and the upper end of the pharynx. It is behind the opening
of the nasal cavity
Egressive Air flow associated with outflowing air, egressive sounds are formed
from an out flowing air stream. It has to do with
exhalation/breathing out or the outflowing air used in
speaking
Ingressive Air flow this is associated with inflowing air, ingressive sounds are
formed from an inflowing airstream. (ie. some sounds are
produced with the air we breathe in).
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Phonation
-
Voice
-
Larynegeal Valving
-
Larynx
-
Vocal folds
-
is the vibration of the vocal folds to produce voice and nonvibration of the folds which results in voiceless sound
refers to laryngeal phonation and it has no direct relation to
the identification of phonenes. This phonation is
reinforced by the supra glottal resonant cavities
is the vibration of the larynx. The larynx could hyper
valve it. Tighten up or have its optimal valving by
producing the most efficient valving. Or there can be
hypovalving characterized by air turbulence
the voice box of speech. It is a structure made up of 9
cartilages muscles, membranes and ligament. The larynx is
located between the trachea and the pharynx. It produces
vibrating air steam for the vocal folds that is enclosed in it.
The larynx is located in the anterior neck region
are long smoothly rounded bands of muscle tissue which
are the vibrating elements. They can adduced, adducted,
lengthened, shortened, tensed relaxed
Vocal folds are about ¾” (17 millimeters) long adult male
but about 12.5 - 17mm in adult female and still shorter in
newborns/children
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ANATOMY AND
PHYSIOLOGY OF
LANGUAGE AND SPEECH
MECHANISM
PROF.GRACE YAWO GADAGBUI
52