Chapter 2 Speech Sounds As human beings we are capable of making all kinds of sounds, but only some of these sounds have become units in the language system. We can analyze speech sounds from various perspectives and the two major areas of study are phonetics and phonology. PHONETICS studies how speech sounds are produced, transmitted, and perceived. Imagine that the speech sound is articulated by a Speaker A. It is then transmitted to and perceived by a Listener B. Consequently, a speech sound goes through a three-step process, as shown in Figure 2.1. Speech Transmission (sound waves) Speech Production Speech Perception (A) (B) Figure 2.1 The process of speech production and perception Naturally, the study of sounds is divided into three main areas, each dealing with one part of the process: • ARTICULATORY PHONETICS is the study of the production of speech sounds. • ACOUSTIC PHONETICS is the study of the physical properties of speech sounds. • PERCEPTUAL or AUDITORY PHONETICS is concerned with the perception of speech sounds. PHONOLOGY is the study of the sound patterns and sound systems of languages. It aims to “discover the principles that govern the way sounds are organized in languages, and to explain the variations that occur” (Crystal, 1997: 162). In phonology we normally begin by analyzing an individual language, say English, in order to determine its PHONOLOGICAL STRUCTURE, i.e. which sound units are used and how they are put together. Then we compare the properties of sound systems in different languages in order to make hypotheses about the rules that underlie the use of sounds in them, and ultimately we aim to discover the rules that underlie the sound patterns of all languages. In this chapter, we will introduce and discuss some of the basic ideas of articulatory phonetics and phonological analysis. 2.1 How speech sounds are made 2.1.1 Speech organs SPEECH ORGANS, also known as VOCAL ORGANS, are those parts of the human body involved in the production of speech (Figure 2.2). It is striking to see how much of the human body is involved in the production of speech: the lungs, the trachea (or windpipe), the throat, the nose, and the mouth. The pharynx, mouth, and nose form the three cavities of the VOCAL TRACT. Speech sounds are produced with an AIRSTREAM as their sources of energy. In most circumstances, the airstream comes from the lungs. It is forced out of the lungs and then passes through the bronchioles and bronchi, a series of branching tubes, into the trachea. Then the air is modified at various points in various ways in the larynx, and in the oral and nasal cavities: the mouth and the nose are often referred to, respectively, as the ORAL CAVITY and the NASAL CAVITY. Inside the oral cavity, we need to distinguish the tongue and various parts of the palate, while inside the throat, we have to distinguish the upper part, called PHARYNX, from the lower part, known as LARYNX. The larynx opens into a muscular tube, the pharynx, part of which can be seen 1 in a mirror. The upper part of the pharynx connects to the oral and nasal cavities. Figure 2.2 The organs of speech (Based on MacMahon, 1990: 7) The contents of the mouth are very important for speech production. Starting from the front, the upper part of the mouth includes the upper lip, the upper teeth, the alveolar ridge, the hard palate, the soft palate (or the velum), and the uvula. The soft palate can be lowered to allow air to pass through the nasal cavity. When the oral cavity is at the same time blocked, a NASAL sound is produced. The bottom part of the mouth contains the lower lip, the lower teeth, the tongue, and the mandible (i.e. the lower jaw). In phonetics, the tongue is divided into five parts: the tip, the blade, the front, the back and the root. In phonology, the corresponding sounds made with these parts of the tongue are often referred to as CORONAL (tip and blade), DORSAL (front and back) and RADICAL (root). 2 At the top of the trachea is the larynx, the front of which is protruding in males and known as the “Adam’s Apple”. The larynx contains the VOCAL FOLDS, also known as “vocal cords” or “vocal bands”. The vocal folds (Figure 2.3) are a pair of structure that lies horizontally with their front ends joined together at the back of the Adam’s Apple. Their rear ends, however, remain separated and can move into various positions: inwards, outwards, forwards, backwards, upwards and downwards. Figure 2.3 The vocal folds (Source: Roca & Johnson, 1999: 15) For most phonetic purposes, however, it is sufficient to say that the vocal folds are either (a) apart, (b) close together, or (c) totally closed. • When the vocal folds are apart, the air can pass through easily and the sound produced is said to be VOICELESS. Consonants [o+r+s] are produced in this way. • When they are close together, the airstream causes them to vibrate against each other and the resultant sound is said to be VOICED. [a+y+c] are voiced consonants. • When they are totally closed, no air can pass between them. The result of this gesture is the glottal stop [>]. 2.1.2 The IPA In 1886, the Phonetic Teachers’ Association was inaugurated by a small group of language teachers in France who had found the practice of phonetics useful in their teaching and wished to popularize their methods. It was changed to its present title of the INTERNATIONAL PHONETIC ASSOCIATION (IPA) in 1897. One of the first activities of the Association was to produce a journal in which the contents were printed entirely in phonetic transcription. The idea of establishing a phonetic alphabet was first proposed by the Danish grammarian and phonetician Otto Jespersen (1860-1943) in 1886, and the first version of the INTERNATIONAL PHONETIC ALPHABET (the IPA chart) was published in August 1888. Its main principles were that there should be a separate letter for each distinctive sound, and that the same symbol should be used for that sound in any language in which it appears. The alphabet was to consist of as many Roman alphabet letters as possible, using new letters and diacritics only when absolutely necessary. These principles continue to be followed today. The IPA chart has been revised and corrected several times and is widely used in dictionaries and textbooks throughout the world. The latest version was revised in 2005. In the IPA chart, the sound segments are grouped into CONSONANTS and VOWELS, which will be discussed in detail in the next section. The consonants are then divided into pulmonic and non-pulmonic consonants: PULMONIC sounds are produced by pushing air out of the lungs, as in most circumstances, while NON-PULMONIC sounds are produced by either sucking air into the mouth, in the case of clicks, or closing the glottis and manipulating the air between the glottis and a place of articulation further forward in the vocal tract, as is the case of implosives and ejectives. 3 The vowels are shown their relevant positions in a cross-sectional diagram of the oral cavity. 4 The “other symbols” are actually a group of consonants that involve more than one place or manner of articulation, which cannot be placed into one of the slots in the consonant chart. The DIACRITICS are additional symbols or marks used together with the consonant and vowel symbols to indicate nuances of change in their pronunciation. The suprasegmentals are used to represent stress and syllables, whereas the last group of symbols is used to show tonal differences and intonation patterns. 2.2 Consonants and vowels In the description of sound segments, a basic distinction is made between consonants and vowels. Consonants are produced “by a closure in the vocal tract, or by a narrowing which is so marked that air cannot escape without producing audible friction”. By contrast, a vowel is produced without such “stricture” so that “air escapes in a relatively unimpeded way through the mouth or nose” (Crystal, 1997: 154). The distinction between vowels and consonants lies in the obstruction of airstream. As there is no obstruction of air in the production of vowels, the description of the consonants and vowels cannot be done along the same lines. 2.2.1 Consonants In the production of consonants at least two articulators are involved. For example, the initial sound in bad involves both lips and its final segment involves the blade (or the tip) of the tongue and the alveolar ridge. The categories of consonant, therefore, are established on the basis of several factors. The most important of these factors are: (a) the actual relationship between the articulators and thus the way in which the air passes through certain parts of the vocal tract, and (b) where in the vocal tract there is approximation, narrowing, or the obstruction of air. The former is known as the Manner of Articulation and the latter as the Place of Articulation. The MANNER OF ARTICULATION refers to ways in which articulation can be accomplished: (a) the articulators may close off the oral tract for an instant or a relatively long period; (b) they may narrow the space considerably; or (c) they may simply modify the shape of the tract by approaching each other. (1) STOP (or PLOSIVE): Complete closure of the articulators is involved so that the airstream cannot escape through the mouth. It is essential to separate three phases in the production of a stop: (a) the closing phase, in which the articulators come together; (b) the hold or compression phase, during which air is compressed behind the closure; (c) the release phase, during which the articulators forming the obstruction come rapidly apart and the air is suddenly released.