Transcript 言語科學 Speech Science Emily Lin, PhD (林永芬)

言語科學
Speech Science
Emily Lin, PhD (林永芬)
Department of Communication Disorders University of Canterbury
Christchurch, New Zealand
Taiwan Academy of Physical Medicine and Rehabilitation Conference:
Current Intervention for Children with Developmental Delay
Taoyuan, Taiwan
December 2, 2006
大綱
• 言語系統 (Speech Production System)
 呼吸 (Respiratory)
 發聲 (Phonatary)
 發音 (Articulatory)
• 言語聲學 (Speech Acoustics)
 The Nature of Sound
 Source-Filter Theory
• 語音和音聲測量 (Speech & Voice Measurement)
(E. Lin)
口語溝通通路
(Perkins & Kent, 1986)
(E. Lin)
言語系統
(Perkins & Kent, 1986)
(E. Lin)
呼吸: 橫膈膜和腹部肌肉的作用
(Perkins & Kent, 1986)
(E. Lin)
呼吸: 胸腔的擴大
(Transverse, Vertical, & Anteroposterior Expansion of Chest)
anteroposterior
(Perkins & Kent, 1986)
(E. Lin)
呼吸: 呼氣和吸氣
(Titze, 1994)
(E. Lin)
呼吸: 肺部空氣量的變化
(Titze, 1994)
(E. Lin)
呼吸: 不同呼吸階段的肌肉控制
(Perkins & Kent, 1986)
(E. Lin)
呼吸: 可能影響呼吸的病症
(Ferrand, 2007)
(E. Lin)
發聲: 聲帶
Endoscopic view of the larynx
(Karnell, 1994)
(E. Lin)
發聲: 呼吸和聲門(glottis)大小的關係
Forced exhalation
Normal inhalation
(Zemlin, 1968, 1988)
Forced inhalation
(E. Lin)
發聲: 發聲前的聲門變化
(Four Stages of Prephonation Phase)
(Zemlin, 1968, 1988)
(E. Lin)
發聲: 聲帶振動的一個週期
(A Glottal Cycle)
(Zemlin, 1968, 1988)
(E. Lin)
發聲: 音頻 (Pitch)
The physical aspects of the vocal folds that determine the rate
of vocal fold vibration:
a. 厚度 (Thickness)
-The thinner, the higher the pitch.
b. 長度 (Length)
-Within each person, the longer length
the vocal folds are stretched to, the higher
the pitch. (But if we compare between subjects,
the longer the vocal folds and thus the more
the mass, the lower the pitch:
female: 12-17 mm; male: 17-20 mm)
Superior view of the
larynx
c. 彈性度 (Elasticity)
-The tenser, the higher the pitch.
(E. Lin)
發聲: 音頻 (Pitch)
(Ferrand, 2007)
(E. Lin)
Vocal folds as a mass-spring oscillator
• Fundamental frequency is positively related
to the stiffness (k), and inversely related to
the mass (m) of the vocal folds
(Titze, 1994)
(E. Lin)
Physical Laws Related to Vocal Fold Vibration
• Equilibrium:

Three conditions of equllibrium:
(a) unstable, (b) neutral, (c) stable
(Titze, 1994)


Only a “stable” system qualifies as an oscillator.
“Stable” equilibrium is characterized by a
“restoring force”, which always accelerates the body
back to the resting position.
-In this example:
-oscillator: the ball
-restoring force: gravity
-resting position: the bottom of the bowl
(E. Lin)
Physical Laws Related to Vocal Fold Vibration
• Oscillation (vibration):


Definition: a repeated back-and-forth movement
Two types of oscillation:
Natural (free) vs. Forced (self-sustaining)
(Titze, 1994)
(E. Lin)
Physical Laws Related to Vocal Fold Vibration
• Continuity law of incompressible flow:
The incompressible flow in a duct/pipe is constant,
regardless of what happens to the area.
v1A1 = v2A2 = constant = U
U: flow
v: velocity
A: area
(Titze, 1994)
(E. Lin)
Physical Laws Related to Vocal Fold Vibration
• Bernoulli’s principle (conservation law):
The total energy in the fluid at any point
along the pipe has two components:
potential energy + kinetic energy = constant
(P + 0.5rv2 = constant)
P: pressure (force per unit area;
e.g., the force exerted on the surface of the duct)
r: fluid density
v: fluid velocity
If the energy is constant, then
as velocity increases,
pressure decreases.
(Perkins & Kent, 1986)
(E. Lin)
Myoelastic-Aerodynamic Theory
•
Vocal folds open and close in a repetitive fashion as a result of
interactions between tissue movement (myoelastic effect) and
fluid flow (aerodynamic effect).
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Vocal folds move together. (active tissue movement)
Narrow constriction in the glottis leads to increased velocity, thus
decreased pressure. (fluid flow)
Vocal folds are further sucked together by negative Bernoulli
pressure in the glottis. (fluid induced tissue inward movement)
Vocal fold closure leads to buildup of subglottal pressure, forcing
the folds to open. (fluid induced tissue outward movement)
Lateral (opening) movement continues till elastic forces in the
tissue retard the movement and reverse it. (tissue recoiling)
(E. Lin)
(Titze, 1994)
Coronal section view of the laryngeal system
(E. Lin)
Body-Cover Theory
Coronal
section
through the
right vocal
fold
(Titze, 1994)
(E. Lin)
Mechanically coupling stiffness
Coronal section of vocal fold
(Titze, 1994)
(E. Lin)
• Oscillator: vocal folds
• Restoring force:
-tissue elasticity
-airflow/pressure change
• Resting position:
-paramedian position
(initially: prephonatory position)
(Titze, 1994)
(E. Lin)
The driving force of the vocal folds
1. Nonuniform tissue movement
•
The movement of the cover can be independent of
the body.
•
Degrees of freedom of the tissue
(the softer the tissue, the more flexible).
2. Time-varying glottal pressure and flow
•
The delayed action between the upper and lower
portions of the vocal folds creates an asymmetric
driving pressure.
3. Asymmetric response of the vocal tract.
(E. Lin)
共鳴 (Resonance): 口腔和鼻腔的分隔
(Karnell, 1994)
Velopharyngeal port
(E. Lin)
共鳴 (Resonance): 鼻音
(Ferrand, 2007)
(E. Lin)
發音: 聲腔
(Perkins & Kent, 1986)
(E. Lin)
發音: 聲腔
(Perkins & Kent, 1986)
(E. Lin)
發音: 母音
(Perkins & Kent, 1986)
(E. Lin)
發音: 子音
(Perkins & Kent, 1986)
(E. Lin)
The Nature of Sound: Sound Transmission
(Ferrand, 2007)
(E. Lin)
The Nature of Sound: Sound Waves
(Ferrand, 2007)
(E. Lin)
The Nature of Sound: Spectrum
(Ferrand, 2007)
(E. Lin)
Source-Filter Theory
Source
spectrum
Filter
spectrum
Output
spectrum
(Titze, 1994)
(E. Lin)
Source-Filter Theory: Vowel
(Titze, 1994)
(E. Lin)
語音和音聲測量
(Speech & Voice Measurement)
• Respiratory function
 Airflow
 Muscle movement: strength, duration, direction
• Laryngeal function


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Airflow
Laryngeal resistance (pressure/airflow)
Acoustic (perturbation, spectral tilt, bandwidth, formant frequency)
physiological (EMG, Airflow, pressure, EGG, PGG, stroboscopy)
• Articulatory function
 Acoustic analysis
 Articulatory movement: Electropalatography,
Electromagnetic Articulography, Visual tracking device
(E. Lin)
參考文獻
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Baken, R. J. (1987). Clinical Measurement of Speech and Voice. Austin, TX: Proed.
Bernthal, J. E. & Bankson, N. W. (1988). Articulation and Phonological
Disorders, 2nd ed. Englewood Cliffs, NJ: Prentice Hall.
Ferrand, C. T. (2007). Speech Science: An Integrated Approach to Theory and
Clinical Practice, 2nd ed. Boston: Allyn & Bacon.
Karnell, M. P. (1994). Videoendoscopy: From Velopharynx to Larynx. San
Diego: Singular Publishing.
Perkins, W. H. & Kent, R. D. (1986). Functional Anatomy of Speech, Language,
and Hearing. Boston: Allyn & Bacon.
Pickett, J. M. (1999). The Acoustics of Speech Communication: Fundamentals,
Speech Perception Theory, and Technology. Boston: Allyn & Bacon.
Titze, I. R. (1994). Principles of Voice Production. Englewood Cliffs, NJ:
Prentice Hall.
(E. Lin)