Human Speech Mechanism and Organs of speech

1. Human Speech Mechanism and Organs of speech

2. Origin of language • Language originates in the Brain • The human body does not possess any special organ exclusively dedicated to the act of speaking. • A combination of organs used for other purposes also serves as organs of speech. • The term ‘organs of speech’ is used in the sense of the organs which are active directly or indirectly in the process of speech production.

3. Phonetics and phonology • Phonetics is the study of speech sounds in a human language system. • Phonology is the study of the selection and patterns of sounds in a single language. It is the study of the way speech sounds combine to make meaningful signs or words in a specific language

4. Speech Mechanism • Mechanism of speech is composed of four processes. • Language processing: content of an utterance is converted into phonemic symbols in the brain’s language centre. • Generation of motor commands to the vocal organs in the brain’s motor centre. • Articulatory movement for the production of speech by the vocal organs based on these motor commands. • Emissions of air sent from the lungs in the form of speech

5. Branches of Phonetics • The study of Phonetics can be divided into Articulatory, Acoustic and Auditory phonetics. • Articulatory phonetics deals with the production of speech sounds by the human speech mechanism. • Acoustic Phonetics is about the transmission of sound and sound waves. • Auditory phonetics deals with the reception and perception of sounds and hearing.

6. Human Speech Organs • Speech functions can be described with reference to three systems in the human body. • The Respiratory System • The Phonatory System • The Articulatory System

8. The Phonatory System • This is composed of the larynx and the vocal cords or vocal folds. • Larynx in the throat is a muscular structure in the upper part of the trachea which contains a pair of muscular bands or folds called the vocal cords. • These are placed horizontally from front to back, joined at the front but separated at the back. The space between the cords is called the glottis.

9. Human Speech Organs

10. Human Speech Organs

11. The Respiratory System • The lungs, the muscles of the chest and the windpipe or trachea provide the air-stream or energy used to produce speech. • This air stream is known as PulmonicEgressive air stream mechanism. • Other organs such as the glottis and the velum can also provide an air stream mechanism. A number of African & S. American languages use these air streams for the production of certain sounds in their language. Sindhi uses the glottalic air stream.

12. Larynx and Vocal Cords

13. Position of the Vocal Cords • When we breathe in & out, the glottis is open, i.e. the vocal cords are drawn wide apart. • When we produce speech sounds with the vocal cords drawn apart, such sounds are called breathed or voiceless sounds. Eg./p/ /t/ /k/ /f/ /h/

14. Voiced Sounds • If the vocal cords are held loosely together, the pressure of the air coming from the lungs makes them vibrate. This vibration produces a musical note called voice. All vowel sounds and consonants like /b/ /d/ /g/ are voiced sounds.

15. Frequency and Pitch • The number of times the vocal cords open and close in one second is known as the frequency of vibration. This determines the pitch of the voice. • The higher the frequency of vibration, the higher is the pitch. • Frequency is a physical measurement while pitch refers to the perception of the listener. • Pitch change is important because it forms the basis of intonation and tone.

16. The Articulatory System

17. The Articulatory System

18. Articulatory System • The articulatory system is contained in the head and throat, above the larynx. It is also known as the supra-glottal vocal tract. • In the articulation of speech sounds, we can divide the speech organs into three parts. • 1.Resonating cavities or chambers such as oral, nasal and pharyngeal.

19. Active and Passive articulators • 2. Articulators such as the lower lip, the tongue, uvula and the lower jaw. These are also called active articulators as they can move and take up positions which affect the quality of sounds produced. • 3. Points of articulation such as the upper lip, the upper teeth, the alveolar ridge, the hard palate and the velum or the soft palate. These are called passive articulators.

20. The pharynx, nose and the mouth including the tongue, the teeth, the roof of the mouth, and the lips form the articulatory system. • The pharynx extends from the top of the larynx to the root of the tongue (the hindermost part of the tongue) which lies opposite to it. The muscles of the pharynx can modify the shape and size of the pharyngeal cavity by contracting or expanding. It can also be modified by the movement of the back of the tongue, by the position of the soft palate and the raising and lowering of the larynx. Each modification affects the quality of the sound we produce.

21. The Lips • Lips which are in the front most position of the oral tract play an important role in the production of speech sounds. • example: for articulation of /p/ /b/ /m/ lips are tightly shut and air is released suddenly. • Lips assume different positions – spread, neutral, or rounded for articulation of different vowel sounds.

22. : The Teeth and the Teeth Ridge (latindentes;adj.dental) • Some consonants are produced with the help of our teeth. • Example: the initial consonant sounds in the English word thinkand that are produced by placing the tip of the tongue between the upper teeth and lower teeth. • The initial consonants in the English words fan and van are produced by placing the upper teeth very lightly on the lower lip.

23. Roof of the Mouth • The roof of the mouth can be divided into three parts. • The hard convex surface just behind the upper front teeth called the teeth ridge or alveolar ridge. • The hard concave surface called the hard palate. • The soft palate or velum.

24. The Teeth Ridge • The teeth ridge or the alveolar ridge is the convex part of the roof of the mouth lying just behind the upper teeth. Consonant sounds as the initial sound in the English words top and drill, by making a firm contact at the teeth ridge with the tip of the tongue and releasing the closure suddenly.

25. 4 Hard and Soft Palate(adj.palatal) • The Hard Palate or Roof of the Mouth: • This is the hard bony surface which we can feel if we move our tongue from the alveolar ridge along the roof of the mouth. Some sounds such as the initial sound in the English word yes are produced at the hard palate.

26. The Soft Palate or Velum • If we move our tongue along the roof of the tongue, it cannot go beyond the roof of the mouth where the bony structure ends and the roof of the mouth becomes soft. This soft portion of the roof of the mouth is known as the soft palate or the velum.

27. Oral Sounds • The soft palate can be raised to create a velic closure or lowered to open a passage. • When it is raised the nasal passage is closed so that no air can escape through the nose. It can escape only through the mouth. The sounds produced in this way are called oral sounds.

28. Position of vocal cords for oral and voiced sounds • u

29. Nasal Sounds • When the velum is lowered the air escapes through the nose in two possible ways. • It can pass through the nose only or it can pass through the nose and the mouth • /m/ /n/ /ng/ are nasal sounds and the other type is called nasalised sound.

30. The Uvula • At the end of the soft palate there is a small pendant-like fleshly tongue called uvula. The back of the tongue can make contact with the uvula for the production of sounds such as the initial sound in the Urdu words Karib and Kaum.

31. The Tongue(latinlingua;adj.lingual) • This is the most flexible of the organs of speech • It can assume different shapes and take up different positions which are significant in speech production. • Can be divided into three parts for convenience of description.

32. Parts of the tongue • Blade – Part of the tongue opposite the teeth ridge when the speech organs are at rest. Its extreme end is called the tip. • Front – part opposite the hard palate • Back – Part opposite the soft palate. • Root – part attached to mouth at the back.

33. The Mouth • The shape of the mouth determines the quality of most of our speech sounds. • The oral cavity represented by the mouth is bound by the teeth in front, the hard palate or the roof of the mouth and the walls of the pharynx at the back. These are fixed.

34. Mouth • The other parts of the mouth like the lips, parts of the tongue, the soft palate and the lower jaw are movable. • The movement of the lower jaw is responsible for the distance between the upper and lower teeth and the shape of the lips which in turn affects the quality of speech sounds particularly vowels.

35. The Nose • The nose or the nasal cavity is made up of the two nostrils which are primarily used for normal breathing. • In the production of speech sounds, the nasal cavity acts as a resonating chamber for nasal sounds. • When the soft palate is lowered as in normal breathing, the air escapes through the nose and mouth. But if an obstruction is created in the mouth to restrict the passage of air through the mouth, then nasal sounds such as m, n, ng are produced.

36. Active & Passive Articulators • Active articulators are those organs of speech that can move and passive articulators are those which are fixed. • The tongue, the lower jaw are active articulators. • The upper jaw, teeth ridge are fixed and passive articulators. • The velum acts as both active and passive articulator.

37. Articulatory Movement • In the production of speech sounds the active articulator move from their position of rest towards the passive articulators. • Example: in the production of the /t/ /d/ /s/ /n/ sounds, the tip and blade of the tongue move from their position of rest to articulate against the teeth ridge.