Introduction to English Phonetics : Chapter First: The Organs of Speech

The Organs of Speech and Its Three Systems 

The organs of the human body that we use for speaking are together called organs of speech. But speech is the secondary function of these organs and their primary functions are breathing, chewing, eating, smelling and tasting. The organs of speech and their speech function can be described under the three systems: the respiratory system, the phonatory system and the articulatory system. 

The Articulatory System/ Articulatory Phonetics: 

When we speak, we produce sounds. But not all sounds are the same. When we  speak , the chest muscles produce an air flow. This air flow goes through an area we call the larynx. There are muscles in the larynx that modify this air flow. Then, this air flow goes through the vocal tract , which ends at the mouth and nostrils and we listen to speech sounds. This is how the air which comes from lungs escapes into the atmosphere. 

But why are the sounds produced different? The reason is that there are large and complex sets of muscles that change the shape of the vocal tract. These different parts are called articulators and the study of them is called articulatory phonetics. 

Let's study the articulators: 

1. The pharynx: it is a tube. It is about 7 cm long in women and about 8 cm in men, and at its top end , it is divided into two. The first part of it is called the back of the mouth and the other is the beginning of the way through the nasal cavity. 

2. The velum or soft palate: the velum allows air to go through the nose and through the mouth. The tongue can touch the velum. Sounds when the tongue touches the velum are called velar sounds. The best examples of velar consonants are ‘k’ and ‘g’. 

3. The hard palate : it is the roof of the mouth.

4. The alveolar ridge: it is a rough part with ridges. It is between the top front teeth and the hard palate. The sounds when the tongue touches the alveolar ridge are called alveolar. For example, ‘t’ and ‘d’ are alveolar consonants.

5. The tongue: it is the most  important articulator and the most  flexible articular. It can move into  different parts of the mouth and can take different shapes. The tongue is divided into five parts. They are : tip, blade, front , back and root.

   

6. The teeth ( upper and lower) : they are also very important articulators. Sounds during the production of which the tongue touches the front teeth are called dental. The examples are θ/, /ð/.

7. The lips : They are very important in speech. Sometimes our lips are pressed together, and we produce  bilabial consonant sounds like ‘p’ and ‘b’. Sometimes our lips and teeth are in contact with each other and we produce labiodental consonant sounds like ‘f’ and v’.

These are the seven main articulators, but there are others like jaws, nose and nasal cavity. 

2. Respiratory System 

The respiratory system includes the lungs, the chest muscles and the windpipe ( trachea) . Our lungs perform the function of breathing or respiration. They can expand and take the outside air in and also push the air out. This is simply inhalation or breathing in and out. In both cases, the air passes through the windpipe ( trachea) . This process produces an airstream that acts as a source of energy. Without airstream speech organs cannot produce a sound. However, the lungs are not the only organ that produce airstream but other organs too. But the airstream coming from the lungs is most commonly used in many of the world languages including Indian and European. This airstream that comes from the lungs is called egressive  pulmonic  airstream.  

3. Phonatory System 

We know that the airstream coming from the lungs is made to change. The first change ( modification) in the airstream is made in the trachea or windpipe. For example, let's pronounce the words ‘seal’ and ‘zeal’ one after another. We will notice ‘a hum’ sound in the sound ‘z’. But no sound is heard in the sound ‘s’. The reason is that we listen to ‘the hum’ sound because the airstream is modified or changed in the trachea.

There are two important parts that we should study in the phonatory system: the first is the larynx and the second is the vocal cords. 

 i) The Larynx: The larynx is in the neck. Its main structure is made of two cartilages. These are hollow and are attached to the top of the trachea. When we breathe in, the air goes through the trachea and the larynx. The front of the larynx comes to a point. This point is called the Adam's Apple. Inside the larynx, there is a pair of lips- like structure. These are called the vocal cords. 

The different positions of the vocal cords:

1. Wide open: When the vocal cords ( vocal folds) are wide open, the air passes freely between them, and so there is no vocal folds vibration.The opening between the vocal folds is called the glottis. When the vocal folds are wide open, we say that the glottis is open. When the vocal folds are wide open and when there is no vibration as the air goes freely, we produce ‘voiceless sounds’. Examples are voiceless consonants like ‘p’, ‘f’ & ‘s’.

2. Narrow Glottis: When the vocal folds are brought close together but not so close as to touch eath other and to create vibration. The result is a fricative sound like ‘h’. It is called a voiceless glottal fricative. It is very much similar to whispering.

3. Glottis in Vibration: When the edges of the vocal folds touch each other, the air going through them produces vibration. And so we get voiced sounds such as ‘b’, ‘d’ and ‘g’. This vibration of the vocal cords ( folds) is called phonation. 

4. Closed Glottis: When the vocal folds are firmly pressed together and the air cannot pass through them, we say that the glottis is closed. Remember during the time of eating and drinking the glottis is closed so that no food or drink enters the windpipe( trachea).  And when all of a sudden, they are drawn apart an explosive sound is produced. This is called the glottal stop. This glottal stop is like the sound of a mild cough. In English, when we pronounce the initial sounds in words like ‘ act’, ‘empty’ and ‘ uncle’, we notice explosive sounds from these initial vowels.