THE ORGANS OF SPEECH AND THE FORMATION OF SOUNDS. CLASSIFICATION OF ENGLISH SPEECH SOUNDS

1. The organs of speech and formation of sounds

A. Speech organs (articulators) - all the sounds we make when we speak are the result of muscles contracting. 
The muscles in the chest that we use for breathing produce the flow of air that is needed for almost all speech sounds. Muscles in the larynx produce many different modifications in the flow of air from the chest to the mouth. After passing through the larynx, the air goes through what we call the vocal tract, which ends at the mouth and nostrils. Here the air from the lungs escapes into the atmosphere. We have a large and complex set of muscles that can produce changes in the shape of the vocal tract, and in order to learn how the sounds of speech are produced it is necessary to become familiar with the different parts of the vocal tract. These different parts are called articulators, and the study of them is called aticulatory phonetics. Articulators produce the sounds of language. Organs used include the lips, teeth, tongue, alveolar ridge, hard palate, velum (soft palate), uvula and glottis.

Speech organs (or articulators above the larynx) are of two types: passive articulators and active articulators.

1. Passive articulators - remain static during the articulation of sound.

- pharynx wall - is a tube which begins just above the larynx. It is about 7 sm. long, and at its top end it is divided into two, one part being the back of the mouth and the other being the beginning of the way through the nasal cavity. If you look in your mirror with your mouth open, you can see the back of the pharynx.

- soft palate (velum) -  is seen in the diagram in a position that allows air to pass through the nose and through the mouth. Often in speech it is raised so that air cannot escape through the nose. It is one of the articulators that can be touched by the tongue. When we make the sounds k and g the tongue is in contact with the lower side of the velum, and we call these velar consonants.

- hard palate - is often called "the roof of the mouth". You can feel its smooth curved surface with your tongue.

- alveolar ridge - is between the top front teeth and the hard palate. You can feel its shape with your tongue. Its surface is really much rougher than it feels, and is covered with little ridges. Sounds made with the tongue touching here (such as t and d) are called alveolar.

- teeth (upper and lower) - are usually shown in diagrams only at the front of the mouth, immediately behind the lips. The tongue is in contact with the upper side teeth for many speech sounds. Sounds made with the tongue touching the front teeth are called dental.

- lips - they can be pressed together (when we produce the sounds p, b), brought into contact with the teeth (as in f,v), or rounded to produce the lip-shape for vowels like u:. Sounds in which the lips are in contact with each other are called biliabial, while those with lip-to-teeth contact are called labiodental.

- uvula

2. Active articulators - move relative to these passive articulators to produce various speech sounds, in different manners. The most important active articulator is the tongue as it is involved in the production of the majority of sounds. The lower lip is other active articulator. But glottis (the part of the larynx consisting of the vocal cords and the slitlike opening between them) is not active articulator because it is only a space between vocal folds.

B. Formation of sounds - in studying articulation, phoneticians explain how humans produce speech sounds via the interaction of different physiological structures.

Generally, articulatory phonetics is concerned with the transformation of aerodynamic energy into acoustic energy. Aerodynamic energy refers to the airflow through the vocal tract. Its potential form is air pressure; its kinetic form is the actual dynamic airflow. Acoustic energy is variation in the air pressure that can be represented as sound waves, which are then perceived by the human auditory system as sound.

Components - the vocal tract can be viewed through an aerodynamic-biomechanic model that includes three main components: air cavities, pistons and air valves

1. Air cavities - are containers of specific volumes and masses. The main air cavities present in the articulatory system are the supraglottal cavity and the subglottal cavity. They are so-named because the glottis, the openable space between the vocal folds internal to the larynx, separates the two cavities. The supraglottal cavity or the orinasal cavity is divided into an oral subcavity (the cavity from the glottis to the lips excluding the nasal cavity) and a nasal subcavity (the cavity from the velopharyngeal port), which can be closed by raising the velum. The subglottal cavity consists of the trachea and the lungs. The atmosphere external to the articulatory stem may also be considered an air cavity whose potential connecting points with respect to the body are the nostrils and the lips.

2. Pistons - are initiators. The term initiator refers to the fact that they are used to initiate a change in the volumes of air cavities, and, by Boyle's Law, the corresponding air pressure of the cavity. The term initiation refers to the change. Since changes in air pressures between connected cavities lead to airflow between the cavities, initiation is also referred to as an air stream mechanism. The three pistons present in the articulatory system are the larynx, the tongue body, and the physiological structures used to manipulate lung volume (in particular, the floor and the walls of the chest). The lung pistons are used to initiate a pulmonic airstream (found in all human languages). The larynx is used to initiate the glottalic airstream mechanism by changing the volume of the supraglottal and subglottal cavities via vertical movement of the larynx (with a closed glottis). 

3. Valves - regulate airflow between cavities. Airflow occurs when an air valve is open and there is a pressure difference between in the connecting cavities. When an air valve is closed, there is no airflow. The air valves are the vocal folds (the glottis), which regulate between the supraglottal and subglottal cavities, the velopharyngeal port, which regulates between the oral and nasal cavities, the tongue, which regulates between the oral cavity and the atmosphere, and the lips, which also regulate between the oral cavity and the atmosphere. Like the pistons, the air valves are also controlled by various muscles.

Initiation of sounds - to produce any kind of sound, there must be movement of air. To produce sounds that people today can interpret as words, the movement of air must pass through the vocal chords, up through the throat and, into the mouth or nose to then leave the body. Different sounds are formed by different positions of the mouth—or, as linguists call it, "the oral cavity" (to distinguish it from the nasal cavity).

2. Classifications of English speech sounds

Sounds of all languages fall under two categories:  vowels and consonants. A vowel is a sound in the articulation of which the air passes through the mouth freely. There is no obstruction to the stream of air. The consonant is a sound in the production of which an obstruction is formed in the mouth by the active organs of articulation. The organs of speech are tense at the place of obstruction. The stream of air is strong especially in the articulation of voiceless consonants as in [p], [t], [k].

A. Vowels - a speech sound that is produced by comparatively open configuration of the vocal tract, with vibration of the vocal cords but without audible friction and is a unit of the sound system of a language that forms the nucleus of a syllable.

Classification of the English Vowel phonemes - we begin the study of English sounds in the course by looking at vowels, and it is necessary to say something about vowels in general before turning to the vowels of English. We need to know in what ways vowels differ from each other. The first matter to consider is the shape and position of the tongue. It is usual to simplify the very complex possibilities by describing just two things: firstly, the vertical distance between the upper surface of the tongue, between front and back, which is raised highest. 

The English vowel phonemes are divided into two large groups: monophtongs and diphtongs. A monophtong is a vowel in the pronunciation of which the organs, principally the tongue and the lips do not change their position through out the duration of the vowel as in the monophtongs  [i:], [i], [e], [æ], [ɑ:], [ɔ:], [ɔ], [u], [ʊ:], [ə],  [ə:], [ʌ],

A diphthong is a vowel sound in the pronunciation of which the organs of speech start in the position of one vowel and glide gradually in the direction of another. There are 8 diphtongs in English [ei], [ai], [oi], [əu], [iə], [ɛə], [uə],[ou]

The vowels are classified according to the following principles:

1. According to the position of the tongue

- on the horizontal movement of the tongue - the vowels are divided into:

• front - [i], [e], [ɛ], [æ]
• front restricted - [ɪ]
• mixed - [ə:], [ə]
• back - [ɑ] [a:],[ɔ], [ɔ:], [u:]
• back-advanced - [ʌ], [u:]

- on the vertical movement of the tongue

• close - [i:], [ɪ], [u:], [ʊ]   
• open - [æ], [a:], [ɔ],[ɔ:]    
• midopen - [e], [ə:], [ə], [ʌ]

2. According to the position of the lips

- rounded - [ə], [ɔ:], [u:], [ʊ]

- unrounded - in the production of which the lips are spread or neutral as in [i:], [ɪ],[e],[æ],[a:],[ʌ],

[ə:], [ə]

3. According to their length

- long - [i:],[ɔ:],[a:],[ə:],[u:] and [æ] in certain positions  

- short - [i], [e], [a], [ə], [u], [ʌ],  and [æ] in certain positions  

4. According to the degree of tenseness

- tense vowels - [i],[ɔ:],[u:],[a:],[ə],

- lax vowels

In the production of tense vowels the organs of speech are tense. All English long vowels are tense. Lax vowels are those in the production of which the muscles of the organs of speech are less tense. All English short vowels are lax. The greater tenseness of the long vowels is connected with their length. Bulgarian vowels aren’t differentiated according their tenseness.

5. According cavity where is produced 

- nasal vowel - is a vowel that is produced with a lowering of the velum so that air escapes both through the nose as well as the mouth. 

- oral vowels - are vowels without this nasalization. Nasal vowels that are distinctive or obligatory are of far more linguistic importance than whether or not speakers of a language tend to nasalize vowels in some instances.

[ Nasal vowel / Oral vowel ]  [ Previous Vowel / Later Vowel ] [ Rounded vowel / Unrounded vowel ]  [ Open vowel / Closed vowel ]

B. Consonants - the quality of the consonant sounds depends on the kind of noise that results when the tongue or the lips obstruct the air passage. Consonants are produced with some form of restriction or closing in the vocal tract that hinders the air flow from the lungs.  Consonants are generally classified according to where in the vocal tract the airflow has been restricted. This is also known as the place of articulation. 

Consonants are classified according the following principles: 

1. According to the manner of production of noise and type of obstruction

- occlusive (stops) consonants: the air passage through the mouth is completely blocked. They may be noise consonants or plosive like [p], [b], [t], [d], [k], [g]  and occlusive sonorants  [m], [n], [ŋ] in which the air passage through the mouth is blocked while the soft palate is lowered so that the air can pass through the nasal cavity.                   

- constrictive: the air passage is not blocked completely but is narrowed (constructed) an uncomplete obstruction - [f], [v], [θ], [ð], [s], [z], [ʃ], [ʒ], [h]

According to the size of narrowing the constrictive consonants are divided into: 

• noise consonants - which are also called fricative consonants because an audible friction is produced [dʒ], [ʒ] and 
• constrictive sonorants - in which the air passage is rather wide, so that no audible friction is produced. Here belongs the consonants - [w], [j], [r], [l]
• occlusive-constrictive: these are noise consonants - [tʃ], [dʒ]
• rolled or thrilled

2. According to the active organ of speech and the place of obstruction (place of articulation) - movement of the tongue and lips can create these constrictions and by forming the oral cavity in different ways, different sounds can be produced:

- Bilabial - when producing a [b], [p] or [m], articulation is done by bringing both lips together.

- Labiodental - [f] and [v] are articulated by placing the upper teeth against the lower lip.

- Interdental - [θ] and [ð] are both spelled as "th" (θ as in think) (ð as in the). They are pronounced by inserting the tip of the tongue between the teeth.

- Alveolar - [t][d][n][s][z][l][r] are produced in many ways where the tongue is raised towards the alveolar ridge.

• [t, d, n] - the tip of the tongue is raised and touches the ridge.
• [s, z] - the sides of the front of the tongue are raised, but the tip is lowered so that air escapes over it.
• [l] - the tip of the tongue is raised while the rest of the tongue remains down, permitting air to escape over its sides. Hence, [l] is called a lateral sound (âm biên).
• [r] [IPA ɹ] - curl the tip of tongue back behind the alveolar ridge, or bunch up the top of the tongue behind the ridge, the air escapes through the central part of the mouth. It is a central liquid.

- Palatal - [ʃ] [ʒ ][tʃ] [dʒ] [j] are produced by raising the front part of the tongue to the palate.

- Velar - [k][g][ŋ] are produced by raising the back part of the tongue to the soft palate or the velum.

- Uvular - [ʀ][q][ԍ] these sounds are produced by raising the back of the tongue to the uvula. The 'r' in French and German may be an uvular trill (symbolized by [ʀ]). The uvular sounds [q] and [ԍ] occur in Arabic. These do not normally occur in English.

- Glottal - [h][ʔ] the sound [h] is from the flow of air coming from an open glottis, past the tongue and lips as they prepare to pronounce a vowel sound, which always follows [h]. if the air is stopped completely at the glottis by tightly closed vocal chords the sound upon release of the chords is called a glottal stop [ʔ]. 

- lingual: they are articulated with the top of the tongue and the blade of the tongue [t], [d]

Here we distinguish 3 types: 
- fore lingual [b], [t], [n], [s] 
- medio lingual [j], 
- back lingual [k], [g], [ŋ]

3. According to the work of vocal cords

- voiceless consonants - in the articulation of which the vocal cords are kept apart as [p], [t], [k], [ʔ], [ɾ], [f], [θ], [s], [ʃ], [tʃ], [h]

- voiced consonants - in the production of which the vocal cords are close together and vibrate [b], [d], [g], [m], [n], [ŋ], [v], [ð], [z], [ʒ], [dʒ], [l], [w]

4. According to the position of the soft palate

- oral – the soft palate is raised

- nasal consonants – in the production of which soft palate is lowered and the air passes through the nasal cavity [m], [n], [ŋ]