The organs of speech

The Organs of Speech

1-nasal cavity  2-lips  3-teeth  4-aveolar ridge  5-hard palate  6-velum (soft palate)  7-uvula  8-apex (tip) of tongue  9-blade (front) of tongue  10-dorsum (back) of tongue  11-oral cavity  12-pharynx  13-epiglottis  14-larynx  15-vocal cords  16-trachea  17-esophagus

 

 

THE SPEECH ORGANS AND THEIR FUNCTIONS

 

Speech is produced in the throat, mouth and nasal passage, but there are no “speech organs” as such, strictly speaking;  all of the organs used in speech have other, and perhaps more fundamental, purpose involving eating and breathing.   Nevertheless the term is familiar and meaninful in the contex of articulatory phonetics, and will be used here.  The speech organs are shown in a diagram, a cross-section of the head and throat.

The  lungs, diaphragm, chest muscles and windpipe also act in the production of speech, but they will not be discussed in detail as their function is more  or less automatic.

Speech is produced by causing a column of enclosed air to víbrate.  It is the same  prosses, basically, as the production of sound by a wind instrument  in music.  Air is forced under pressure from the lungs trough the windpipe (trachea), to the voice box  (larnyx), a structure that sits on top of the windpipe and contains  the vocal cords, as they are called. (These are not cords  at all, really,  and would  be more properly named band sor membranes).  The vocal cords have the capability of closing off entirely the opening (glottis) and can hold considerable air pressure  (as when a person coughs or strains to lift a heave  weight).  They can also assume other positions. They may be  wide open, allowing the air to pass unimpeded.  Or they may be closed almost but not quite completely, so that  the scaping air, forced through the narrow opening between  them causes them to víbrate like the reed in a musical instrument.  This vibration  makes tthe all-important  vocal tone. known  technically as voice, without  which speech would be impossible.  Speech sounds that have this tone as part of their makeup are called voiced., and those without it are called  unvoiced orvoiceless.  Varying the amount of tensión on the vocal cords causes the vocal tone to vary in quality  and in number of cycles per second; in other words, the timbre and pitch of the tone can be changed voluntarily, within limits. by the speakers.

The air stream issuing from the larynx w ith or without voice, can now be modified in many ways;  that is, we are at the stage of  articulation.  Almost all the parts of the throat and lower  head that are accesible to the air stream can take part in articulation.  For discussion purposes, we can divide these parts into three groups;  resonating cavities, ariticulators, and points of articulation.

 

RESONATING CAVITIES

The size, the shape, and the material composition of the vessel enclosing a vibrating  air column  all  have important effects  on the quality of the sound that comes from it.  There are quite a few spaces in the speech tract that effect sounds by their resonating  qualities; in acousting terms, their reinforce (amplify) certain frecuencies and and suppress or weaken (dampen) others. In addition  to te sinuses and other spaces in the head, which function  passively and without the control of the speaker, the resonating cavities involved in speech production are these:  the pharnyx, the space formed by the root of the tongue and the walls of the throat, which affects  the sound by its shape but is not actively used in English;  thenose, which adds its quite distinctive quality to the sounds if the air is allowed to pass through it whether or not the mouth is involved at the same time; and finally, the mouth, the most important of all because it contains a number of highly mobile organs and can assume a tremendous number of different shapes.

ARTICULATORS

These are movile organs that can be brough close to, or into contact withi, various locations in the speech tract (known as points of articulation) so as to stop or impede the free passage  of the air stream.  The manner of articulation is determined by the kind of closure or near closure that is made, as well as its manner of release.  The articulators are the lips, especially the lower one; the tongue, usually divided into four parts; tip, front, middle, and back; the uvula; and, to an extent, the jaw, through its role is minor (it is posible to speak quite clearly with the jaws clenched, as ventriloquist do).

 

POINTS OF ARTICULATION

These are fixed locations againts  which the movile articulators operate in order to produce speech sounds: the teeth, the gums, the alveolar ridge, the various parts of the palate (sometimes called “hard” palate  to distinguish it from the “soft” palate or velum),  the velum, the walls of the pharynx and the glotis.

 

 

Speech apparatus structure. Organ functions. English sound articulation.

To master English pronunciation, a pupil should first learn speech apparatus structure, speech organs and their functions.

We pronounce sounds by exhaling from the lungs. Through the trachea the outgoing air comes into the glottal cavity – the trachea’s upper part with thevocal cords.

Vocal Cords

These are 2 muscular elastic folds able to approach with stretching and distance with relaxing. Space between them is the glottis. Stressed cords make air flow shake them. Their vibration produces the tone/voice we hear in articulating vowels, consonants and sonants like [а:], [n], [z]. When the cords are relaxed and apart, air freely goes through the glottis. Such is their position in pronouncing voiceless consonants like [s], [p]. Touching the glottal cavity, we can feel cords vibration in pronouncing vowels/sonants and no vibration in pronouncing voiceless consonants.

Above the glottal cavity are the pharyngeal cavity, mouth cavity and nasal cavity. Their capacity influences sound quality.

Mouth Cavity

From the pharyngeal cavity exhaled air can go via the mouth cavity (with the soft palate up) or  nasal cavity (with the soft palate down). In the first case oral sounds form, in the second nasal sounds. English has 3 nasals ([m], [n], [ŋ]) and one glottal sound ([h]). The rest are oral sounds.

Tongue

It’s the main articulation organ. It’s very flexible and mobile in different positions in the mouth cavity to produce vowels and consonants. The tongue ascent in the mouth cavity depends on mouth opening (lower jaw position).

For easier articulation description, the tongue divides into 3 parts: the front partwith its tipped front edge, middle part and back part. When relaxed, the front part is opposite the alveolar ridge on the hard palate, the middle part opposite thehard palate and the back part opposite the soft palate. All tongue surface is called the dorsal surface while its front part surface – the predorsal surface.

The tongue’s front part is the most active. It only forms various obstacles (full and partial) in consonant articulation. In vowel articulation it’s passive behind the lower teeth.

The tongue’s middle and back parts constitute its bulk. It’s less flexible though able to move horizontally and vertically helping form vowel sounds.

Minor Organs

Teeth and lips can form full and partial obstacles in articulating consonants like [b], [v], [w]. Lip and lower jaw positions regulate mouth opening size and form in pronouncing vowels like [i], [o:].

Classification

Speech organs can be mobile and immobile, active and passive. Mobile are the tongue, lips, soft palate with the uvula, lower jaw, vocal cords. Immobile are the upper jaw, teeth, alveolar ridge and hard palate

 

 

 

 

 

1. The Lungs

The airflow is by far the most vital requirement for producing speech sound, since all speech sounds are made with some movement of air. The lungs provide the energy source for the airflow. The lungs are the spongy respiratory organs situated inside the rib cage. They expand and contract as we breathe in and out air. The amount of air accumulated inside our lungs controls the pressure of the airflow.

2. The Larynx & the Vocal Folds

The larynx is colloquially known as the voice box. It is a box-like small structure situated in the front of the throat where there is a protuberance. For this reason the larynx is popularly called the Adam’s apple. This casing is formed of cartilages and muscles. It protects as well as houses the trachea (also known as windpipe, oesophagus, esophagus) and the vocal folds (formerly they were called vocal cords). The vocal folds are like a pair of lips placed horizontally from front to back. They are joined in the front but can be separated at the back. The opening between them is called glottis. The glottis is considered to be in open state when the folds are apart, and when the folds are pressed together the glottis is considered to be in close state.

 

 
The opening of the vocal folds takes different positions:

1. Wide Apart: When the folds are wide apart they do not vibrate. The sounds produced in such position are called breathed or voiceless sounds. For example: /p/f/θ/s/.
2. Narrow Glottis: If the air is passed through the glottis when it is narrowed then there is an audible friction. Such sounds are also voiceless since the vocal folds do not vibrate. For example, in English /h/ is avoiceless glottal fricative sound.
3. Tightly Closed: The vocal folds can be firmly pressed together so that the air cannot pass between them. Such a position produces a glottal stop / ʔ / (also known as glottal catch, glottal plosive).
4. Touched or Nearly Touched: The major role of the vocal folds is that of a vibrator in the production of speech. The folds vibrate when these two are touching each other or nearly touching. The pressure of the air coming from the lungs makes them vibrate. This vibration of the folds produces a musical note called voice. And sounds produced in such manner are called voiced sounds. In English all the vowel soundsand the consonants /v/z/m/n/are voiced.

 
Thus it is clear that the main function of the vocal folds is to convert the air delivered by the lungs into audible sound. The opening and closing process of the vocal folds manipulates the airflow to control the pitch and the tone of speech sounds. As a result, we have different qualities of sounds.

3. The Articulators

Articulators transform the sound into intelligible speech. They can be either active or passive. They include the pharynx, the teeth, the alveolar ridge behind them, the hard palate, the softer velum behind it, the lips, the tongue, and the nose and its cavity. Traditionally the articulators are studied with the help of a sliced human head figure like the following:

 

(i) The Pharynx: The pharynx lies between the mouth and the food passage, that is, just above the larynx. It is just about 7cm long in the case of women and 8cm long in the case of men.

 

(ii) The Roof of the Mouth: The roof of the mouth is considered as a major speech organ. It is divided into three parts:

 

a. The Alveolar Ridge/Teeth Ridge: The alveolar ridge is situated immediately after the upper front teeth. The sounds which are produced touching this convex part are calledalveolarsounds. Some alveolar sounds in English include: /t/d/.

 
b. The Hard Palate: The hard palate is the concave part of the roof of the mouth. It is situated on the middle part of the roof.

 
c. The Velum or Soft Palate: The lower part of the roof of the mouth is called soft palate. It could be lowered or raised. When it is lowered, the air stream from the lungs has access to the nasal cavity. When it is raised the passage to the nasal cavity is blocked. The sounds which are produced touching this area with the back of the tongue are called velarsounds. For example: /k/g/.

 

(iii) The Lips: The lips also play an important role in the matter of articulation. They can be pressed together or brought into contact with the teeth. The consonant sounds which are articulated by touching two lips each other are called bilabial sounds. For example, /p/ and /b/ are bilabial sounds in English. Whereas, the sounds which are produced with lip to teeth contact are calledlabiodental sounds. In English there are two labiodental sounds: /f/ and /v/.

 

Another important thing about the lips is that they can take different shapes and positions. Therefore, lip-rounding is considered as a major criterion for describing vowel sounds. The lips may have the following positions:

 

a. Rounded: When we pronounce a vowel, our lips can be rounded, a position where the corners of the lips are brought towards each other and the lips are pushed forwards. And the resulting vowel from this position is a rounded one. For example, /ə ʊ/.

 
b. Spread: The lips can be spread. In this position the lips are moved away from each other (i.e. when we smile). The vowel that we articulate from this position is an unrounded one. For example, in English /i: /is a long vowel with slightly spread lips.

 
c. Neutral: Again, the lips can be neutral, a position where the lips are not noticeably rounded or spread. And the articulated vowel from this position is referred to as unrounded vowel. For example, in English /ɑ: / is a long vowel with neutral lips.

 

 

(iv) The Teeth: The teeth are also very much helpful in producing various speech sounds. The sounds which are made with the tongue touching the teeth are called dental sounds. Some examples of dental sounds in English include: /θ/ð/.

 

(v) The Tongue: The tongue is divided into four parts:

 
a. The tip: It is the extreme end of the tongue.

b. The blade: It lies opposite to the alveolar ridge.

c. The front: It lies opposite to the hard palate.

d. The back: It lies opposite to the soft palate or velum.

 

The tongue is responsible for the production of many speech sounds, since it can move very fast to different places and is also capable of assuming different shapes. The shape and the position of the tongue are especially crucial for the production of vowel sounds. Thus when we describe the vowel sounds in the context of the function of the tongue, we generally consider the following criteria:

 

• Tongue Height: It is concerned with the vertical distance between the upper surface of the tongue and the hard palate. From this perspective the vowels can be described as close andopen. For instance, because of the different distance between the surface of the tongue and the roof of the mouth, the vowel /i: /has to be described as a relatively close vowel, whereas /æ / has to be described as a relatively open vowel.

 

• Tongue Frontness / Backness: It is concerned with the part of tongue between the front and the back, which is raised high. From this point of view the vowel sounds can be classified asfront vowels and back vowels. By changing the shape of the tongue we can produce vowels in which a different part of the tongue is the highest point. That means, a vowel having the back of the tongue as the highest point is a back vowel, whereas the one having the front of the tongue as the highest point is called a front vowel. For example: during the articulation of the vowel / u: / the back of the tongue is raised high, so it’s a back vowel. On the other hand, during the articulation of the vowel / æ / the front of the tongue is raise high, therefore, it’s afront vowel.

 

 

(vi) The Jaws: Some phoneticians consider the jaws as articulators, since we move the lower jaw a lot at the time of speaking. But it should be noted that the jaws are not articulators in the same way as the others. The main reason is that they are incapable of making contact with other articulators by themselves.