Speech Production Process

1. Speech Production Process

2. 4 Processes in Speech Production • Respiration • Phonation • Resonance • Articulation

3. Respiration: Power Mechanism • Provides the energy for sound • Breathing is an aerodynamic process • a difference in air pressure is created between the thoracic cavity and the atmospheric pressure outside the body

4. 2 Phases of Breathing • Inhalation - muscles of the thoracic cavity expand the chest; air pressure decreases and air is taken in • air pressure is less in thorax than in atmosphere and air flows in • Exhalation - when the pressure is greater in thorax, air flows out • there is a decrease in chest cavity and an increase in air pressure

5. Breathing for Speech vs Breathing for Life • Breathing for speech uses same muscles, but is controlled more • exhalation phase is longer than inhalation phase for speech • Breathing for life, inhalation and exhalation phases are same

6. Phonation: Vibrating Mechanism • Phonation is the rapid opening and closing of the vocal folds for sound • the vocal folds lie horizontally in the larynx • they attach anteriorly to the thyroid cartilage and posteriorly to the artynoid cartilages; they are free in the middle • the opening in the middle of the vocal folds is the GLOTTIS

7. Phonation (con’t) • adduction of the arytnoids closes the vocal folds • the middle of the vocal folds vibrate to and from midline • vibration of the vocal folds produces voicing • Position of vocal folds • open (abducted) • closed (adducted)

8. 3 major aspects of voice influenced by vocal fold movement • Pitch - frequency of vibration • the rate of vocal fold vibration is called the FUNDAMENTAL FREQUENCY • this is measured in terms of Hz or cps • therefore, if the vocal folds vibrate 200 cps it is a fundamental frequency of 200Hz • an increase in pitch involves an increase in frequency (hi pitch; hi frequency) • the frequency of vocal fold vibration depends on the mass and length of the vocal folds and the tension

9. 3 major aspects (con’t) • Loudness - intensity of sound • involves the amount of energy generated by the vocal fold movements • intensity increases with increased air pressure from the lungs and increased amplitude of the vocal fold vibration • involves the amount of energy generated by the vocal fold movements • intensity increases with increased air pressure from the lungs and increased amplitude of the vocal fold vibration • Quality - the sound quality of the voice • this is affected by the pattern of movementof the vocal folds

10. Resonance: The characteristic quality of the voice • The speech mechanism is a resonator -- it is like an air-filled tube (closed on one end and open at the other end) • the fundamental frequency generated at the vocal folds is resonated in the vocal tract that is now also vibrating -- the vibration of the vocal tract is the HARMONIC FREQUENCY • every body or object has its own natural frequency • those frequencies that match the vocal tract’s natural frequency will be amplified this is resonance

11. Resonance (con’t) • Pharynx is the primary resonator • recall the 3 parts of the pharynx (nasopharynx, oropharynx, laryngopharynx) • the nasopharynx and oropharynx are the 2 resonating systems • these 2 systems provide resonance to sounds that pass through the oral and nasal cavities

12. Articulation • Serves to produce the different configurations which make up the different speech sounds

13. Dynamics of Speech Production • Speech is a dynamic rather than a static phenomenon • the articulators are in a state of constant movement during speech • Individual speech sounds are described in terms of target positions; ongoing speech is better thought of in terms of movement

14. Dynamics of Speech Production (con’t) • Sounds in a word don’t follow each other like printed letters • spoken sounds overlap with each other • this is referred to as CO-ARTICULATION

15. Co-articulation • as the articulators are in the process of forming one sound, their positioning prepares them for the sound that follows • speech sounds influence and are influenced by other sounds within a phonetic environment • the dynamic nature of speech means that we are planning events before they occur • we may articulate one segment before completing another • we may be as much as several segments ahead or behind in our motor activity

16. Co-articulation • Important clinically because a client cannot simply be taught to pronounce a given sound in one simple way • need to provide practice in a variety of phonetic environments • Examples of co-articulation • /iki/ - point of artic for /k/ is more forward (palatal) than velar • / uku/ - point of artic for /k/ is more posterior (uvular) than velar • /aka/ - point of artic for /k/ is actually velar • sneeze ~ snooze; see ~ Sue

17. Co-articulation (con’t) • Why do we have co-articulation? • It’s not because we’re lazy. • There are too many demands on the speech mechanism than there is time to fulfill them • normal conversation is produced at a rate of between 10-20 segments/second which implies a maximum of 100msec/segment • however, it takes much longer than this to complete any speech gesture and then return to the starting point • THEREFORE, something has to give -- thus, compromise gestures are made

18. Co-articulation (con’t) • It is true that dialects and registers of speech (formal vs informal) differ in the amount of coarticulation that can be made • non-native speakers want to learn this allowable accommodations in order to sound more normal • the second language learner often has a hypercorrect pronunciation that sounds strange because it lacks the usual shortcuts that native speakers take • Need to distinguish co-articulation from assimilation • co-articulation means that 2 different sounds were being articulated simultaneously • one tongue movement was made for both sounds

19. Assimilation • Refers to changes that cross phonemic boundaries and results in a major phonetic change • The resulting change is to a different sound (phoneme) • Co-articulation results in non-phonemic differences • In assimilation, there is a major change in the place of articulation, manner of articulation, or voicing of a segment, such that it falls into a different phonemic category • Examples of assimilation • I miss you; got you; had you; phone booth

20. Types of Assimilation (direction of accommodation) • Regression assimilation - a particular sound influences the sound immediately preceding it • EX: miss you • also referred to anticipatory, or right-to-left assimilation • Progressive assimilation - a given sound produces changes in the sound that follows • EX: cats dogs • left-to-right assimilation

21. Other Combinatory Phenomena • Elision (ellipsis) - when a segment or several segments are left out of a word when it is pronounced • dialectal differences in elision, e.g., “interesting”, “secretary” • Epenthesis - the insertion of a sound, generally to break up consonant clusters or to provide a transition between sounds

22. Other Combinatory Phenomena (con’t) • Metathesis - when two adjacent segments are reversed • EX: “ask” [æks] • dialectal metathesis