TRADITIONAL ARTICULATORY PHONETICS
Early phoneticians used phonetic symbols as abbreviations for full descriptions of the sounds of language. In order to afford a precise account of the sounds of language, they used the vocal tract activities during sound articulation as their classification criterion. In other words, each sound in any language is considered to be a complex pattern of overlapping waves moving through air. These patterns are thought to be caused by different configurations of the various organs of speech as air travels from the lungs out through the nose or mouth or both.
So, phoneticians argued that a sound can be best described if we describe it in terms of air modifications that occur in the vocal organ of speakers. In fact, some phoneticians turned to anatomists for help in this connection. This gained so much importance that a good number of books on phonetics included chapters devoted partially or completely to a discussion of the functions of human respiratory system. A discussion of the human vocal organ is, therefore, necessary here.
The primary function of the human vocal organ is not speech production. In fact, this organ has been developed for purposes of breathing. In other words, the primary function of this organ is respiration. We take oxygen into our lungs (inhalation) and send carbon dioxide out of our lungs (exhalation) in order to remain alive. Speech is only the peripheral or subsidiary function of human vocal organ also called the human vocal tract. Speech sounds are not the only sounds produced by human vocal tract. All of us sneeze, snore, grunt, groan, scream, hiccup, cough, etc. It is, however, impossible to find any language in which these noises are part of its speech articulation system.
In order to produce speech, we modify the flow of air that passes between our lungs and the outside atmosphere. These modifications are normally applied to the flow of carbon dioxide during exhalation to produce a class of sounds technically called egressive sounds. In some African languages, however, people make some speech sounds when they are inhaling air (ingressive sounds). It can, therefore, be concluded that air stream mechanism is at the heart of speech.
In addition to their normal names, many of the parts of the vocal tract have Latin or Greek fancy names. The adjectives we use to describe sounds made with each part are usually based on the Latin/Greek name.
In phonetics, the terms velum, pharynx, larynx, and dorsum are used as often, or more often, than the simpler names. Many of the names that appear in the sagittal section of the human vocal tract are already known to you. There are, however, some names that you may find new. It is, therefore, necessary to provide a definition for each of these new terms.
The alveolar ridge is a short distance behind the upper teeth. It is a change in the angle of the roof of the mouth. (In some people it's quite abrupt, in others very slight.) Sounds which involve the area between the upper teeth and this ridge are called alveolars. Hard palate is the hard portion of the roof of the mouth. The term "palate" by itself usually refers to the hard palate. Soft palate/velum is the soft portion of the roof of the mouth, lying behind the hard palate. The velum can also move: if it lowers, it creates an opening that allows air to flow out through the nose; if it stays raised, the opening is blocked, and no air can flow through the nose. Uvula is the small, dangly thing at the back of the soft palate. The uvula vibrates during the /r/ sound in many French dialects. Pharynx is the cavity between the root of the tongue and the walls of the upper throat. Tongue blade is the flat surface of the tongue just behind the tip. Tongue body/dorsum refers to the main part of the tongue, lying below the hard and soft palate. The body, specifically the back part of the body (hence "dorsum", Latin for "back"), moves to make vowels and many consonants. Tongue root is the lowest part of the tongue in the throat. Epiglottis refers to the fold of tissue below the root of the tongue. The epiglottis helps cover the larynx during swallowing, making sure that food goes into the stomach (through the esophagus) and not into the lungs. A few languages use the epiglottis in making sounds. English is fortunately not one of them. Vocal folds/vocal cords are folds of tissue (i.e., membranes) stretched across the airway to the lungs. They can vibrate against each other, providing much of the sound during speech. Glottis refers to the opening between the vocal cords. During a glottal stop, the vocal cords are held together and there is no opening between them. Larynx is the structure that holds and manipulates the vocal cords. The "Adam's apple" in males is the bump formed by the front part of the larynx.
As it was mentioned in the previous chapter, human beings can not only produce sounds but also noise by means of their vocal tracts. All of us have the experience of coughing after catching cold or flu. We also sneeze, snore, grunt, groan, scream, etc. You, however, cannot find any one language in which words are formed as sequences of these noises. There is a quite simple reason for this. Noises interfere with the primary functions of our vocal organs, that of respiration. In addition, they cause pain and bruise in different parts of the vocal tract. Now, you can imagine what happens to the health of an individual if he had to use these noises in his speech. In fact all natural languages employ sounds (i.e., consonants and vowels). These are well organized sounds which do not cause problems for respiration.
In order to produce speech sounds, the flow of pulmonary air in the vocal tract must somehow be modified. These modifications are of four main types: (1) complete blockage followed by sudden release, (2) complete blockage followed by gradual release, (3) constriction or narrowing, and (4) no blockage at all. In fact, these modification types have been used in traditional phonetics as the criteria for the classification of speech sounds. These modifications are technically referred to as manner of articulation. These modifications do not occur at one single part of the vocal tract. Rather, they may happen at any part of the super-glottal (from the glottis upwards) section of the vocal tract. These places (sometimes called articulators) include the lips, the teeth, the alveolar ridge, the palate, the velum, and the glottis. Place of articulation is the technical term which is used to refer to the places along the vocal tract at which air modifications take place. In addition to place and manner of articulation, speech sounds can be voiced or unvoiced (voiceless) depending on whether the vocal cords are set into vibration by the impact of pulmonary air. This phenomenon is technically referred to as voicing.
