Hossein Sameti Department of Computer Engineering Sharif University of Technology

2  The study of the anatomy of the organs of speech is required as a background for articulatory and acoustic phonetics.  An understanding of hearing and perception is needed in the field of both speech synthesis and speech enhancement and is useful in the field of automatic speech recognition.

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4  Lungs and trachea : ◦ source of air during speech. ◦ The vocal organs work by using compressed air; this is supplied by the lungs and delivered to the system by way of the trachea. ◦ These organs also control the loudness of the resulting speech. ◦ The trachea and lungs together constitute the pulmonary tract.

5  The Larynx : ◦ This is a complicated system of cartilages and muscle containing and controlling the vocal cords. Principle parts are :  Cricoid cartilage  Thyroid cartilage  Arytenoid cartilage  Vocal cords glottis. ◦ The place where the vocal folds come together is called the glottis.

6 fold s Vocal folds During breathing

7  The Vocal Tract : ◦ Laryngeal pharynx  beneath epiglottis ◦ Oral pharynx  behind tongue, between epiglottis and velum ◦ Nasal pharynx  Above velum, rear end of nasal cavity ◦ Oral cavity  Forward of the velum and bounded by lips, tongue and palate ◦ Nasal cavity  Above the palate and extending from the pharynx to the nostrils

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15  The operation of the system is divided into two functions : ◦ Excitation ◦ Modulation Excitation (glottis) Modulation (vocal tract) Radiate speech

16 AHEE EH OHOO Duck Call

17  Excitation : is done in several ways ◦ Phonation (making of a voiced sound)  This is the oscillation of the vocal cords  The arytenoid cartilages close and stretch the vocal cords  When air forced through the vocal, they vibrate  The opening and closing of the cords breaks the airstream up into pulses

18 pitch.  The repetition rate of the pulses is termed pitch.  At low levels of air pressure oscillation may become irregular, this irregularities are known as “vocal fry”.  Speech sounds accompanied by phonation are called voiced; others, unvoiced or mute. ◦ Whispering (speak softly)  The vocal cord are drown together, but with small triangular opening between arytenoid cartilages

19 ◦ Frication  Frication can occur with or without phonation ◦ Compression stop plosive  If the release is abrupt and clean, the sound is a stop or plosive  If gradual and turbulent, the sound can pass into the related fricative and is termed an affricative

20 ◦ Vibration  If air is forced through a closure other than the vocal cords, vibrations may be set up  Modulation ◦ This is what we do to impose information on the glottal output  Articulatory phonetics: how the organs of speech are positioned to produce any given speech sound  Acoustic phonetics: what the measurable acoustical correlates of any given speech sound are and how acoustical features in general correspond to phonetic and articulatory ones

21  Hearing  Hearing is a process which sound is received and convert into nerve impulse  Perception  Perception is the post-processing within the brain by which the sounds heard are interpreted and given meaning

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24  The ear is divided into three parts: ◦ The outer ear:  Consist of the pinna  Consist of the pinna (visible, convolved cartilage)  Its convolved shape is provide some directional cues  The external canal  The external canal (external auditory meatus)  Uniform tube, 2.7 cm long by 0.7 cm across through  It has a number of resonant frequencies at 3 kHz  The eardrum  The eardrum (tympanic membrane)  Is a stiff, conical structure at the end of the meatus  It vibrate in response to the sound

25 ◦ The middle ear  Is an air-filled cavity tympanic membrane  Separated from the outer ear by the tympanic membrane ovalround window  Connected to the inner ear by the oval and round window eustachian tube  Connected to the outside world by way of the eustachian tube

26  eustachian tube  eustachian tube permit equalization of air pressure between the middle air and the surrounding atmosphere (ossicles)  the middle ear contain three tiny bone (ossicles)  Malleus (hammer)  Incus (anvil)  Stapes (stirrup)  The function of the ossicles  Impedance transformation  Amplitude limiting

27 ◦ The inner ear  vestibular apparatus  Used for balance and sensing orientation  The round and oval window  Cochlea  Is a snail-shape passage  communication with the middle ear via the round and oval window  It consist the transducers which convert acoustical vibration to verve impulses

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