Transcript Speech Production Process

Speech Production Process
4 Processes in Speech Production
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Respiration
Phonation
Resonance
Articulation
Respiration: Power Mechanism
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Provides the energy for sound
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Breathing is an aerodynamic process
• a difference in air pressure is created between
the thoracic cavity and the atmospheric pressure
outside the body
2 Phases of Breathing
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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
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Exhalation - when the pressure is greater in
thorax, air flows out
• there is a decrease in chest cavity and an
increase in air pressure
Breathing for Speech vs Breathing for Life
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Breathing for speech uses same muscles,
but is controlled more
• exhalation phase is longer than inhalation phase
for speech
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Breathing for life, inhalation and exhalation
phases are same
Phonation: Vibrating Mechanism
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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
Phonation (con’t)
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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)
3 major aspects of voice influenced
by vocal fold movement
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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
3 major aspects (con’t)
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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 movement of the vocal
folds
Resonance: The characteristic
quality of the voice
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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
Resonance (con’t)
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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
Articulation
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Serves to produce the different
configurations which make up the different
speech sounds
Dynamics of Speech Production
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Speech is a dynamic rather than a static
phenomenon
• the articulators are in a state of constant
movement during speech
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Individual speech sounds are described in
terms of target positions; ongoing speech is
better thought of in terms of movement
Dynamics of Speech Production (con’t)
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Sounds in a word don’t follow each other
like printed letters
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spoken sounds overlap with each other
• this is referred to as COARTICULATION
Co-articulation
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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
Co-articulation
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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
Co-articulation (con’t)
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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
Co-articulation (con’t)
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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
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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
Assimilation
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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
Types of Assimilation (direction of
accommodation)
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Regression assimilation - a particular sound
influences the sound immediately preceding
it
• EX: miss you
• also referred to anticipatory, or right-to-left
assimilation
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Progressive assimilation - a given sound
produces changes in the sound that follows
• EX: cats dogs
• left-to-right assimilation
Other Combinatory Phenomena
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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”
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Epenthesis - the insertion of a sound,
generally to break up consonant clusters or
to provide a transition between sounds
Other Combinatory Phenomena
(con’t)
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Metathesis - when two adjacent segments
are reversed
• EX: “ask” [æks]
• dialectal metathesis