Sounds of Speech as Acoustic and Articulatory Units PDF

CHAPTER 2 Sounds of Speech as Acoustic and Articulatory Units 2.1. Acoustic Aspect of Speech Sounds. 2.2. Articulatory Aspect of Speech Sounds. 2.3. The Main Criteria of the Articulatory and Acoustic Classification of Speech Sounds. 2.4. The Articulatory Classification of English Consonants. 2.5. Di...

CHAPTER 2 Sounds of Speech as Acoustic and Articulatory Units 2.1. Acoustic Aspect of Speech Sounds. 2.2. Articulatory Aspect of Speech Sounds. 2.3. The Main Criteria of the Articulatory and Acoustic Classification of Speech Sounds. 2.4. The Articulatory Classification of English Consonants. 2.5. Differences in the articulation Bases of the English and Russian Consonants. 2.6. The Articulatory Classification of English Vowels. 2.7. Differences in the Articulation Bases of the English and Russian Vowels. 2.1. ACOUSTIC ASPECT OF SPEECH SOUNDS As V.A. Vassilyev points out, sound is a physical phenomenon, a kind of energy generated by some vibrating body (a string, a tuning fork or the vocal cords) set into vibration by the application of some external force (a blow or the pressure of air). This energy travels in waves through the air and another medium. Sounds can be periodical (the vibrations of a physical body are rhythmical) and non-periodical (the vibrations are not rhythmical). The auditory impression of periodical waves is a musical tone. The auditory impression of non-periodical waves is noise. 19 The sound has a number of physical properties which all exist and manifest themselves simultaneously, but each of them can be singled out and separated from the others for purposes of analysis. V.A. Vassilyev remarks that the first property is frequency which is the number of vibrations per second. Sound waves may follow one another at different rates of frequency. Therefore, the number of vibrations per second varies greatly. Dependent on the frequency of vibrations is the length of the sound wave, i.e. the distance between the points having the same phase (position) in two adjacent waves. Wave length is proportional to the frequency of vibrations: the higher the frequency, the shorter the wave length. Our perception of the frequency of repeated pressures on the eardrum is the pitch of the sound. The greater the frequency, the higher the pitch, and vice versa. The frequency of the sound depends on the mass, length and tension of the vibrator. The greater the mass of the vibrator, the slower its vibrations, and the lower the pitch. Some people’s vocal cords are thicker and heavier than those of others and their voices are lower than the voices of those with thinner and lighter vocal cords. The longer the vibrator, the slower the vibrations, the lower the frequency and the pitch. A man’s voice is lower than a woman’s partly because his vocal cords are longer. As the tension increases, the frequency increases and the pitch rises. The second physical property of the sound is intensity, changes in which are perceived as variations in the loudness of the sound. The intensity is produced by the amplitude of vibrations and it is measured in 20 decibels. The intensity and frequency of the sound are closely interdependent. Sounds can only exist and move in time. In other words, any sound has a certain duration. The duration, or length, of a sound is the quantity of time, during which the same vibratory motion is maintained. For this reason, the duration of a sound is often referred to as its quantity. The duration of speech sounds is usually measured in milliseconds. In speech there are no definite boundaries between different speech sounds: one speech sound gradually passes into another. Therefore, it is extremely difficult to measure the length of speech sounds exactly. These physical properties of speech sounds will be referred to further in this course. 2.2. Articulatory Aspect of Speech Sounds Speech is impossible without the work of the following four mechanisms: − the power mechanism − the vibrator mechanism − the resonator mechanism − the obstructor mechanism This division is not rigid, because the four mechanisms are closely interconnected and the speech organs forming part of one mechanism may form at the same time part of another mechanism. The power mechanism consists of the diaphragm, the lungs, the bronchi, the windpipe (or trachea), the glottis, the larynx, the mouth cavity 21 and the nasal cavity. The function of this mechanism is to supply energy in the form of air pressure and to regulate the force of the air-stream. The vibrator mechanism (the voice producing mechanism) consists of the vocal cords. They are in the larynx. They are two horizontal folds of elastic tissue. They may be wide open (for breath), completely closed (for glottal stop [ʔ]) and incompletely closed and vibrating (for voice). So voice is produced by the vocal cords vibration. The pitch of the voice depends on the frequency of vibration: the higher the frequency, the higher the pitch of the sound produced. The space between the vocal cords is called the glottis. S.F. Leontyeva points out that according to the data of acoustic investigations there are two more sources that participate in the production of speech sounds besides the vocal cords: the turbulent noise (it results from some constriction in the flow of air) and the impulse wave (it is formed when the complete construction to the flow of air in the mouth cavity is suddenly broken). These sources of speech sounds can work separately or simultaneously. For example, the vocal cords produce vibration in the articulation of vowels, the turbulent noise helps to produce voiceless constrictive consonants [f, s, ʃ], the impulse wave helps to produce voiceless plosive consonants [p, t, k]. The resonator mechanism consists of the pharynx, the mouth cavity and the nasal cavity. These three cavities function as the principal resonator. It influences the formation of the sounds and their quality, i.e. its main function is to form the sounds and intensify them. Each cavity has boundaries, or walls, which are formed by various parts of the speech apparatus. 22 Fig. 1: 1 – the diaphragm, 2 – the lungs, 3 – the bronchi, 4 – the windpipe, 5 – the glottis, 6 – the larynx, 7 – the mouth cavity, 8 – the nasal cavity Some of them are more or less soft and movable (the soft palate, the tongue, the lower jaw) while the others are hard and fixed (the teeth, the hard palate). The obstructor mechanism consists of the tongue, the lips, the teeth, the soft palate with the uvula, the hard palate and the alveolar ridge. This mechanism helps to create an obstruction for producing consonant sounds. There are two types of articulatory obstruction: complete (when 23 two organs of speech come in contact with each other and the air passage through the mouth is blocked) and incomplete (when an articulating organ is held so close to the point of articulation as to narrow or constrict the air passage without blocking it). Fig. 2: 1 – the mouth cavity, 2 – the pharynx, 3 – the nasal cavity Fig. 3: 1 – the tongue (a – the blade with the tip, b – front part, c – back part), 2 – the lips, 3 – the teeth, 4 – the soft palate with the uvula, 5 – the hard palate, 6 – the alveolar ridge The bulk of the tongue can be approximately divided into the blade with the tip, the front part (middle part) and the back part (dorsum). The tip of the tongue can occupy a number of positions in the production of English and Russian forelingual consonants. The lips can be rounded, 24 slightly protruded or spread. The lower lip may move close to the upper teeth. The two lips can close to block the air stream. The teeth also act as an obstruction to the air stream. The upper teeth are the most important for the articulation. The alveolar ridge can be felt with the tip of the tongue as a corrugated ridge just behind the upper front teeth. These four mechanisms work simultaneously and each speech sound is the result of the simultaneous work of all of them. 2.3. THE MAIN CRITERIA OF THE ARTICULATORY AND ACOUSTIC CLASSIFICATION OF SPEECH SOUNDS S.F. Leontyeva draws our attention to the fact that articulatory differences between vowels, consonants and sonorants depend on the following criteria: − the presence or absence of an articulatory obstruction to the air stream in the larynx or in the supra-glottal cavities; − the concentrated or diffused character of muscular tension; − the force of exhalation. On the basis of these criteria consonants may be defined as sounds in the production of which (a) there is an articulatory obstruction to the air stream (complete or incomplete); (b) muscular tension is concentrated in the place of obstruction; (c) the force of exhalation is rather strong. Vowels may be defined as sounds in the production of which (a) there is no articulatory obstruction to the air stream; (b) muscular tension is diffused; (c) the force of exhalation is rather weak. 25 Sonorants are sounds intermediate between noise consonants and vowels because they have features common to both. The obstruction is complete or incomplete, but narrow enough to produce noise. Muscular tension is concentrated in the place of obstruction, but the force of exhalation is rather weak. English sonorants are: [m, n, ŋ, l, w, r, j]. 2.4. THE ARTICULATORY CLASSIFICATION OF ENGLISH CONSONANTS Russian phoneticians classify English consonants according to the following principles: − work of the vocal cords and the force of exhalation; − active organ of speech and the place of articulation; − manner of noise production and the type of obstruction; − position of the soft palate. 1. According to the work of the vocal cords and the force of exhalation English consonants are divided into voiced [b, d, ɡ, z, v, ð, ʒ, m, n, ŋ, l, r, j, w, dʒ] and voiceless [p, t, k, s, f, θ, h, ʃ, ʧ]. The force of exhalation and the degree of muscular tension are greater in the production of voiceless consonants therefore they are called “fortis”, which means “strong, energetic”. Voiced consonants are called “lenis”, which means “soft, weak”, because the force of exhalation and the degree of muscular tension in their articulation are weaker. The English consonants [h, m, n, ŋ, l, w, r, j] do not enter the fortis-lenis opposition according to some phoneticians. In Russian such energy contrast doesn’t play an important role. 26 2. According to the position of the active organ of speech against the place of articulation English consonants are classified into labial, lingual and glottal. Labial consonants are subdivided into bilabial and labiodental. Bilabial consonants are produced with both lips. They are [p, b, m, w]. Labiodental consonants are articulated with the lower lip against the edge of the upper teeth. They are [f, v]. Lingual consonants are subdivided into forelingual, mediolingual and backlingual. Forelingual consonants are articulated with the tip of the blade of the tongue. According to the position of the tip of the tongue they may be apical (articulated by the tip of the tongue against either the upper teeth or the alveolar ridge) – [θ, ð, t, d, l, n, s, z], cacuminal (articulated by the tongue tip raised against the back part of the alveolar ridge) – [r] and dorsal (there are no dorsal consonants in English). According to the place of articulation forelingual consonants may be interdental, dental, alveolar, post-alveolar and palato-alveolar. Interdental consonants are articulated against the upper teeth with the tip. They are [θ, ð]. Alveolar consonants are articulated with the tip of the tongue against the alveolar ridge. They are [t, d, s, z, n, l]. Post-alveolar consonants are articulated with the tip of the tongue against the back part of the alveolar ridge. In English it is [r]. Palato-alveolar consonants are articulated with the tip of the tongue against the alveolar ridge, but the front part of the tongue is raised towards the hard palate. They are [ʧ, ʤ, ʃ, ʒ]. There are no dental (articulated with the blade of the tongue against the upper teeth) consonants in English. 27 Mediolingual consonants are produced with the front part of the tongue raised high to the hard palate. In English it is [j]. Backlingual consonants are also called velar. They are produced with the back part of the tongue raised towards the soft palate. They are [k, ɡ, ŋ]. The glottal consonant [h] is articulated in the glottis. 3. According to the manner of noise production and the type of obstruction English consonants can be classified in the following way. From the view point of the obstruction, which is formed in their articulation, they are occlusive (complete obstruction) and constrictive (incomplete obstruction). According to the principle of voice or noise prevalence, Russian phoneticians suggest a subdivision of the group of occlusive and the group of constrictive consonants into noise consonants (in their production noise prevails over tone) and sonorants (in their production tone prevails over noise). According to the manner of the production of noise, occlusive noise consonants are divided into plosive consonants or stops – [p, b, t, d, k, ɡ] and affricates – [ʧ, ʤ]. In the production of plosive consonants, the speech organs form a complete obstruction which is then quickly released with plosion. In the production of affricates, the speech organs form a complete obstruction which is then released so slowly that considerable friction occurs at the point of articulation. They are also called occlusiveconstrictive (there is a combination of the two obstructions). There are different opinions on the nature of English affricates. The most extreme are the views expressed by B. Bloch and G. Trager who deny the existence of affricates as monophonemic entities and state that they 28 are biphonemic sequences. The other extreme point of view is that expressed by D. Jones and I. Ward who state that there are six or even eight affricates in the system of English consonants: [ʧ, ʤ, ts, dz, tr, dr, tθ, dð]. Russian phoneticians consider affricates as units which are articulatory and acoustically indivisible and morphologically unique. In English the only occlusive-constrictive consonants are [ʧ, ʤ]. In the production of occlusive sonorants [m, n, ŋ] the speech organs form a complete obstruction in the mouth cavity which is not released, the soft palate is lowered and the air escapes through the nasal cavity. English constrictive noise consonants (fricatives) are [f, v, θ, ð, s, z, ʃ, ʒ, h]. In their production the speech organs form an incomplete obstruction. In the production of constrictive sonorants, the air passage is fairly wide so that the air passing through the mouth does not produce audible friction and tone prevails over noise. Constrictive sonorants may be median [w, j, r] and lateral [l]. In the production of median sonorants, the air escapes without audible friction over the central part of the tongue, the sides of the tongue being raised. In the production of lateral sonorants, the tongue is pressed against the alveolar ridge or the teeth, and the sides of the tongue are lowered, leaving the air passage open along them. 4. According to the position of the soft palate all English consonants are divided into oral and nasal. When the soft palate is raised and the air from the lungs escapes through the mouth cavity, oral consonants are produced. When the soft palate is lowered and the air escapes through the nasal cavity, nasal consonants are produced. They are [m, n, ŋ]. 29 2.5. DIFFERENCES IN THE ARTICULATION BASES OF THE ENGLISH AND RUSSIAN CONSONANTS S.F. Leontyeva differentiates some peculiarities of the articulation bases in English and in Russian which cause the differences in the systems of consonants in these two languages. They are the following: 1. The English forelingual consonants are articulated with the apicoalveolar position of the tip of the tongue. The Russian forelingual consonants are mainly dorsal: in their articulation the tip of the tongue is passive and lowered, the blade is placed against the upper teeth [т, т’, д, д’, н, н’, с, с’, з, з’, ч’, ц]. The Russian forelingual apical consonants are only [л, л’, ш, ш’, ж, ж’]. 2. In the production of the Russian consonants the bulk of the tongue is mainly in the front-mid part of the mouth resonator. In the production of the English forelingual consonants the tip of the tongue and the front edges are very tense. It results in the depression in the front part of the tongue, which enlarges the size of the front resonator. 3. The English voiceless consonants [p, t, k, f, s, ʃ, ʧ] are pronounced more energetically than similar Russian consonants. The English voiced consonants [b, d, ɡ, v, ð, z, ʒ, ʤ] are not replaced by the corresponding voiceless sounds in word-final positions and before voiceless consonants ['biɡ ˎteibl]. The English voiceless consonants [p, t, k] are aspirated, when followed by a stressed vowel and not preceded by [s]. 4. Consonants in English which have no counterparts in Russian are: [w, θ, ð, ʤ, r, ŋ, h]. 30 5. There is no opposition between palatalized and non-palatalized consonants in English. The most common mistakes that may result from the differences in the articulation bases of the English and Russian languages are the following: − dorsal articulation of the English forelingual apical [t, d]; − the use of the Russian rolled [р] instead of the English postalveolar [r]; − the use of the Russian [х] instead of the English glottal [h]; − mispronunciation of the English interdental [θ, ð]: the use of [s, f] for [θ] and [d, z] for [ð]; − the use of the forelingual [n] instead of the backlingual velar [ŋ]; − the use of the labio-dental [v, в] instead of the bilabial [w]; − absence of aspiration in [p, t, k] when they occur initially; − weak pronunciation of voiceless fortis [p, t, k, f, s, ʃ, ʧ]; − devoicing of voiced [b, d, ɡ, v, ð, z, ʒ, ʤ] in the terminal position. 2.6. THE ARTICULATORY CLASSIFICATION OF ENGLISH VOWELS The first linguist who tried to describe and classify vowels for all languages was D. Jones. He invented the system of 8 Cardinal Vowels on the physiological bases. It is supposed to be an international standard set of vowel sounds chosen to form a scale of reference. According to D. Jones, they can be produced with the bulk of the tongue at the four cardinal points in the front part of the mouth cavity and at the four cardinal points 31 in the back part of the mouth cavity. But in spite of the theoretical significance of the Cardinal Vowel System its practical application is limited. Russian phoneticians classify English vowels according to the following principles: − position of the lips; − position of the tongue; − length; − degree of tenseness and the character of the end; − stability of articulation. 1. According to the position of the lips English vowels are classified into rounded (labialized) [ʊ - u:, ɒ - ɔ:] and unrounded (non-labialized). Rounded vowels are produced when the lips are more or less rounded and slightly protruded. Unrounded vowels are produced when the lips are spread or neutral. The main effects of lip rounding are to enlarge the mouth cavity and to diminish the size of the opening of the mouth cavity. Both of these deepen the pitch. 2. According to the position of the tongue it is the bulk of the tongue that is the most important in the production of vowels. It can move forward and backward, it can be raised and lowered in the mouth cavity. So Russian phoneticians divide vowels according to the horizontal and vertical movements of the tongue. According to the horizontal movements of the tongue vowels are subdivided into back [ɒ, ɔ:, u:] (when the bulk of the tongue is in the back part of the mouth, while the back of the tongue is raised in the direction of the soft palate), back-advanced [ʊ, ɑ:] (when the back part of the tongue is raised highest towards the soft palate), front [i:, e, æ] (when the bulk of the 32 tongue is in the front part of the mouth, while he front of the tongue is raised in the direction of the hard palate), front-retracted [ɪ] (when the front part of the tongue is raised highest towards the hard palate) and central [ɜ:, ə, ʌ] (when the tongue is almost flat and its central part is raised towards the juncture between the hard and soft palate). According to the vertical movements of the tongue English vowels are subdivided into high (close) [i:, ɪ, ʊ, u:], mid-open (half-open, mid) [e, ɜ:, ə, ɔ:] and low (open) [ʌ, æ, ɑ:, ɒ]. High (close) vowels are produced when one of the parts of the tongue comes close to the roof of the mouth and the air passage is narrowed, but not so much as to form a consonant. Low (open) vowels are produced when the raised part of the tongue is very low in the mouth, and the air passage is very wide. Mid-open (mid) vowels are produced when the raised part of the tongue is half-way between its high and low positions. Each of the subclasses is subdivided into vowels of narrow variation and vowels of broad variation. 3. According to the length English vowels are subdivided into (historically) long and (historically) short. Vowel length may depend on a number of linguistic factors: position of the vowel in a word (in the terminal position a vowel is the longest, it shortens before a voiced consonant and it is the shortest before a voiceless consonant: be – bead – beat), word stress (a vowel is longer in a stressed syllable than in an unstressed syllable), the number of syllables in a word ([ɜ:] in verse is longer than in university), the character of the syllabic structure. Besides vowel length depends on the tempo of speech: the higher the rate of speech the shorter the vowels. 33 4. According to the degree of tenseness traditionally long vowels are defined as tense (when the muscles of the lips, tongue, cheeks and the back walls of the pharynx are tense) and short vowels are defined as lax (when these organs are relatively relaxed). English vowels can be checked and unchecked according to the character of their end. The checked vowels are those which occur in stressed closed syllables, ending in a fortis voiceless consonant: [e] in [bet]. These vowels are pronounced without any lessening in the force of utterance towards their end. They are abruptly interrupted by the following voiceless consonant and they can only occur in a closed syllable. The unchecked vowels are those which are pronounced with lessening the force of utterance towards their end. Therefore, they have weak end and occur terminally, or are followed by a lenis voiced consonant: [i:] in [bi:], [ɑ:] in [kɑ:d]. There are no checked vowels in Russian. All of them are unchecked. 5. According to the stability of articulation English vowels are subdivided into monophthongs (simple vowels) and diphthongs (complex vowels) by Russian phoneticians. English monophthongs are pronounced with more or less stable lip, tongue and mouth walls position (the organs of speech do not perceptibly change their position throughout the duration of the vowel). They are [ɪ, e, æ, ɒ, ʊ, ʌ, ə, ɑ:, ɔ:, ɜ:]. Diphthongs consist of two vowel elements pronounced so as to form a single syllable. In their pronunciation the organs of speech start in the position of one vowel and glide gradually in the direction of another vowel, 34 whose full formation is generally not accomplished. The first element of an English diphthong is called the nucleus. It is strong, clear and distinct. The second element is rather weak. It is called the glide. English diphthongs are [eɪ, aɪ, ɔɪ, aʊ, əʊ, iə, eə, uə]. Besides these diphthongs, there are two vowels in English [i:] and [u:] which may have a diphthongal pronunciation. In the articulation of these vowels the organs of speech change their position but very slightly. These vowels are called diphthongoids. According to S.F. Leontyeva diphthongs are defined differently by different authors. One definition is based on the ability of a vowel to form a syllable (as in the diphthong only one element serves as a syllabic nucleus, a diphthong is a single sound). Another definition of a diphthong as a single sound is based on the instability of the second element. Some scientists define a diphthong from the accentual point of view (as only one element is accented and the other is unaccented, a diphthong is a single sound). D. Jones defines diphthongs as unisyllabic sounds in the articulation of which organs of speech change their position. N. Trubetskoy also defines diphthongs as unisyllabic and states that the parts of a diphthong cannot belong to two syllables. L. Zinder adds that phonemically diphthongs are sounds that cannot be divided morphologically. The classification of English vowels suggested by Russian scientists is more exact from the articulatory point of view and more simple for teaching purposes. 35