Human Speech: Study Of Sounds?

The study of sounds in human speech is called phonetics.It has the following branches :-

1)Articulatory phonetics
2)Acoustic phonetics
3)Auditory phonetics

Articulation : Articulation means producing sounds from the mouth.Thus,this branch of phonetics deals with the production of sounds,their description,and their transcription (i.e writing them with the help of symbols )

Acoustic phonetics :Acoustic phonetics is the study of physical properties of the sounds themselves.There are machines which give bands of frequencies for sounds.Other features of sounds can also be studied.

Auditory Phonetics:Auditory phonetics is the study of reception of the sound by ear and its processing in the brain.

In other words,we study (1)how sounds are produced, (2) how they travel from the mouth to the ear, and (3) how they are perceived by the air and the brain.In this topic we shall only learn articulatory phonetics.

The Production of Speech Sounds :-

Let us first look at the mouth where the speech sounds are produced.Diagram I will help you locate the main articulators i.e organs which help us in producing sounds.

Sounds are made by the air striking against the articulators.This air comes in the form of a stream from the lungs.This is known as the pulmonary stream.It is also known as egressive stream, i.e the stream of air which goes out of the mouth.

Sounds can also be produced by taking in air into the mouth.This is called the Ingressive air stream.

1) Larynx :-

The larynx is a box-like space which allows the air from the lungs to pass through it.

2)Vocal cords:-

In the beginning of the larynx are vocal folds,or vocal cords.They are two bands of muscles lying opposite to each other.


It is the tube which begins above the larynx (i.e the passage which goes down to the lungs).It is approximately 7cm long in women and 8cm in men.At the top it divides into two.One part goes into the nose and the other in the back of the mouth..
                                When the air passes through,the vocal cords can open and close very fast.This is called vibration and it can be form 70 o 1000 times per second.The vibration is called voicing.If you say and keep your tongue in the same position saying zzzz you will hear a buzzing sound.This is the vibration of vocal cords.You can place your fingers on the throat and feel the vibration.If you want to switch it off say ssssss and it will cease.Now you know that /z/ is a Voiced sound and /s/ is an unvoiced sound.Other sounds are also distinguished like this.t
(4)Nasal Cavity:- 

Let us look at the space in the nose.It is also called the nasal cavity.It has air in it which can produce a kind of humming noise called Resonance.

The nasal cavity can be made larger if the soft plate is lowered.As the soft plate is a movable bit of flesh it can divide or connect the nasal and the oral cavities.If it is lowered the volume if air which will vibrate will be more.Now if the mouth is blocked and all the air out of the nose we get what is called Nasal effect.
If your nose is blocked at the back of the nasal cavity,you will not be able to nasalize your sounds.If however,your soft plate is permanently lowered,nasalization will increase.

(5) The Oral Cavity :-

Most of the articulators are in the cavity of the mouth or the oral cavity,Let us discuss them one by one..

(a) The Lips :-

The  lips can close together stopping the air.This action creates sounds which are called Stops or Plosives.They are called plosives because the air is stopped for a very short time and then goes out or in,i.e explodes or implodes.Two such sounds are /p/ and /b/.Say then and feel how your lips close together.Speakers of  Urdu and Hindi do not use implosive sounds in their languages.They are produced by sucking the air inwards.Try to say /p/ and pull the air in.You will produce an implosive sound.If you cannot do it,request a Sindhi friend to say /b/ as used for a goat in the language.You will hear an implosive /b/.The lips can also be rounded or brought close together without meeting each other,These actions too  produce sounds which we will describe later.

(b) The teeth :-
The tongue can be behind the teeth or between them for certain sounds.The lower tip meets the upper teeth if we produce the sounds /f/ and /v/

(c) Alveolar Ridge :-

Just behind the upper teeth is a slightly raised longish ridge called alveolar ridge.Some sounds are produced when the tongue touches or comes near the ridge.

(d)Hard Plate :-

It is a hard sloping place behind the alveolar ridge.If you take your tongue back from the alveolar ridge you can feel it.

(e) Soft Plate :-

It is a soft fleshly place behind the hard plate.It is also called the velum and sounds produced by the tongue touching it or coming near it are called Velar sounds..

(f) Uvula :-

It is a triangular piece of flesh hanging down from the roof of the mouth.You can see it in a mirror if you open your mouth keeping your tongue down.

(g) The Glottis :-

This is the place between the vocal cords.All glottal sounds-sounds coming deep from the throat-come from it........