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
Quality - the sound quality of the voice
this is affected by the pattern of movement of 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 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