The production of speech sounds

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.

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.



Fig.
1 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.)




Fig. 2 Sub-divisions
of the tongue

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.