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Speech Sounds:
Looking toward the classification and description of speech sound - at how speech sounds are produced. We considered the functions the different organs of speech perform in the production of speech sounds. We shall now discuss how speech sounds can be described and classified.
Normally, when we produce a speech sound, we intend to transmit it so that it is heard. As such, therefore, a speech sound can be studied at three stages - the production stage, the transmission stage and the reception stage. Correspondingly, we can describe and classify a speech sound in articulatory terms, acoustic terms and auditory terms, respectively.
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| Sound Portrait |
In other, words, we can describe how the movements of the speech organs modify the air from the lungs in order to produce a given sound (articulatory terms), the physical properties a sound has (acoustic terms) and the features of the sound that are perceived by the listener (auditory terms). Clearly, a complete and exhaustive description of a sound which takes into account articulatory, acoustic and auditory terms would be very complex and cannot be dealt with at this stage. Therefore, we shall, for the present concentrate on the description and classifications of sounds mainly in articulatory terms and partly in auditory terms. The sounds regarded as 'vowels' are described in articulatory terms and on the basis of auditory impressions, and those regarded as 'consonants' are best described in terms of their articulation.
Vowel and Consonant:
Before we proceed with the description and classification of speech sounds, we need to understand the categories - 'vowel' and 'consonant' and try and define them satisfactorily.
Vowel and Consonant are popularly defined with reference to the letters of the alphabet. Thus the letters a, e, i, o, u are called 'vowels' and the rest are 'consonants'. This definition is misleading because 'vowel' and 'consonant' are essentially cate glories of speech sounds. When we label the letters of the alphabet as 'wow' and 'consonant' we probably do it on the basis of the assumption that there is perfect correspondence between the letters and the sounds they stand for. This Correspondence, unfortunately, is not perfect in any language, least of all in English.
'Vowel' and 'Consonant' are also defined in phonetic and linguistic terms. When we define them in phonetic terms, we do so with reference to their production, when we define them in linguistic terms we refer to their function in a given language. In phonetic terms, a vowel is a sound for whose production the oral passage is unobstructed, so that the air can flow from the lungs to the lips and beyond without being stopped, without having to squeeze through a narrow construction, which would cause audible friction.
A consonant, on the other hand, is a sound for whose production the air current is completely stopped, or is forced through a narrow constriction which causes audible friction. Let us look at a few examples. For instance the English word 'bar'. The vowel represented by the letters 'ar', is produced with the mouth wide open and the tongue low in the mouth. The air passage is unobstructed and the air, passes into the atmosphere outside without any friction. The sound is therefore called a vowel. The sound represented by the letter 'b' is produced by a complete closure of the oral passage of air at the two lips, and then the sudden release of the air held behind the closure. Thus, there is an obstruction, for a while, to the flow of air from the lungs. Because of this obstruction the resultant sound is regarded as a consonant.
Take for instance, the English word see. The sound represented by the letter 'see' is produced by raising the front of the tongue fairly high, so that the passage between the tongue and the hard palate is fairly narrow but not narrow enough to cause any audible friction in the sound produced. The sound is therefore, regarded as a vowel. In the production of the s-sound in the English word see, the tip and blade of the tongue rise so high towards the teeth ridge that the passage of air is very narrow and the air passes out with audible friction. Thus the sound is a consonant
As we have just seen, the phonetic definition of 'vowel' and 'consonant' does not depend on any other criteria, nor does it depend on the rules of any particular language. But if we describe 'vowel' and 'consonant' in linguistic terms, then we need to study the function of a sound in a given language. Let us take the initial sounds in the English words yell and wind. In the production of these sounds there is no obstruction to the air flow and no narrowing to cause audible friction. The two sounds, in phonetic terms must therefore be regarded as vowels. But the English language regards them as consonants, because they function as consonants. They always occupy the position of consonants in English words, and take the article a, rather then 'an' before them unlike English vowels. Thus we get a yell, a wind not an yell or an wind.
Having classified sounds into the two broad categories of 'vowel' and 'consonant we shall further sub-classify each category in the next two units. But before we do so let us revise what we have talked about in this unit.
Conclusion:
In this Unit we have described the functions of the organs of speech that comprise the three systems, i.e. the Respiratory system, the Phonatory system and the Articulatory system of the Speech Mechanism. We have seen that each of these organs has an important role to play in the production of speech sounds.
We have seen that a speech sound can be studied at the production stage, the transmission stage and the reception stage. Corresponding to these stages a speech sound can be classified and described in articulatory terms, acoustic terms and auditory terms. However, it would not be possible at this stage to describe speech sounds in terms of all these three. For the present it would suffice to describe certain sounds in articulatory terms and certain sounds in auditory as well as articulatory terms.
Speech sounds are classified into two broad phonetic categories i.e. 'vowel' and 'consonant'. A vowel is described as a speech sound in the production of which there is no obstruction or narrowing so as to cause friction. All other sounds are under the category 'consonant'.
'Vowel' and 'Consonant' can also be described in linguistic terms i.e. in terms of their function in a given language.