Organs of speech organs & their functions

The production of speech sounds
Articulators above the larynx
All the sounds we make when we speak are the result of muscles
contracting. The muscles in the chest that we use for breathing
produce the flow of air that is needed for almost all speech
sounds; muscles in the larynx produce many different
modifications in the flow of air from the chest to the mouth.
After passing through the larynx, the air goes through what we
call the vocal tract , which ends at the mouth and nostrils. Here
the air from the lungs escapes into the atmosphere. We have a
large and complex set of muscles that can produce changes in the
shape of the vocal tract, and in order to learn how the sounds of
speech are produced it is necessary to become familiar with the
different parts of the vocal tract. These different parts are called
articulators , and the study of them is called articulatory
phonetics .

The articulators

i) The pharynx is a tube which begins just above the
larynx. It is about 7 cm long in women and about 8 cm in
men, and at its top end it is divided into two, one part
being the back of the mouth and the other being the
beginning of the way through the nasal cavity. If you
look in your mirror with your mouth open, you can see
the back of the pharynx.

ii) The velum or soft palate is seen in the diagram in a
position that allows air to pass through the nose and
through the mouth. Yours is probably in that position
now, but often in speech it is raised so that air cannot
escape through the nose. The other important thing
about the velum is that it is one of the articulators that
can be touched by the tongue. When we make the
sounds k and g the tongue is in contact with the lower
side of the velum, and we call these velar consonants.

iii) The hard palate is often called the "roof of the
mouth". You can feel its smooth curved surface with your
tongue.

iv) The alveolar ridge is between the top front teeth and
the hard palate. You can feel its shape with your tongue.
Its surface is really much rougher than it feels, and is
covered with little ridges. You can only see these if you
have a mirror small enough to go inside your mouth
(such as those used by dentists). Sounds made with the
tongue touching here (such as t and d ) are called
alveolar.

v) The tongue is, of course, a very important articulator
and it can be moved into many different places and
different shapes. It is usual to divide the tongue into
different parts, though there are no clear dividing lines
within the tongue. Fig. 2 shows the tongue on a larger
scale with these parts shown: tip , blade, front , back and
root . (This use of the word "front" often seems rather
strange at first.)

vi) The teeth (upper and lower) are usually shown in
diagrams like Fig. 1 only at the front of the mouth,
immediately behind the lips. This is for the sake of a
simple diagram, and you should remember that most
speakers have teeth to the sides of their mouths, back
almost to the soft palate. The tongue is in contact with
the upper side teeth for many speech sounds. Sounds
made with the tongue touching the front teeth are called
dental .

vii) The lips are important in speech. They can be
pressed together (when we produce the sounds p , b ),
brought into contact with the teeth (as in f , v), or
rounded to produce the lip-shape for vowels like uù .
Sounds in which the lips are in contact with each other
are called bilabial , while those with lip-to-teeth contact
are called labiodental .
The seven articulators described above are the main ones used in
speech, but there are three other things to remember. Firstly, the
larynx could also be described as an articulator - a very complex
and independent one. Secondly, the jaws are sometimes called
articulators; certainly we move the lower jaw a lot in speaking.
But the jaws are not articulators in the same way as the others,
because they cannot themselves make contact with other
articulators. Finally, although there is practically nothing that we
can do with the nose and the nasal cavity , they are a very
important part of our equipment for making sounds (what is
sometimes called our vocal apparatus), particularly nasal
consonants such as m , n .
Again, we cannot really describe the
nose and the nasal cavity as articulators in the same sense as (i)
to (vii) above.

Fig. 1 is a diagram that is used frequently in the study of
phonetics. It represents the human head, seen from the side,
displayed as though it had been cut in half. You will need to look
at it carefully as the articulators are described, and you will often
find it useful to have a mirror and a good light placed so that you
can look at the inside of your mouth.