???? Speech Science

1
????Speech Science

• Emily Lin, PhD (???)
• 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

2
??

• ???? (Speech Production System)
• ?? (Respiratory)
• ?? (Phonatary)
• ?? (Articulatory)
• ???? (Speech Acoustics)
• The Nature of Sound
• Source-Filter Theory
• ??????? (Speech Voice Measurement)

(E. Lin)
3
??????
(Perkins Kent, 1986)
(E. Lin)
4
????
(Perkins Kent, 1986)
(E. Lin)
5
?? ???????????
(Perkins Kent, 1986)
(E. Lin)
6
?? ????? (Transverse, Vertical,
Anteroposterior Expansion of Chest)
anteroposterior
(Perkins Kent, 1986)
(E. Lin)
7
?? ?????
(Titze, 1994)
(E. Lin)
8
?? ????????
(Titze, 1994)
(E. Lin)
9
?? ???????????
(Perkins Kent, 1986)
(E. Lin)
10
?? ?????????
(Ferrand, 2007)
(E. Lin)
11
?? ??
Endoscopic view of the larynx
(Karnell, 1994)
(E. Lin)
12
?? ?????(glottis)?????
Forced exhalation
Normal inhalation
Forced inhalation
(Zemlin, 1968, 1988)
(E. Lin)
13
?? ???????? (Four Stages of Prephonation
Phase)
(Zemlin, 1968, 1988)
(E. Lin)
14
?? ????????? (A Glottal Cycle)
(Zemlin, 1968, 1988)
(E. Lin)
15

• ?? ?? (Pitch)
• The physical aspects of the vocal folds that
  determine the rate
• of vocal fold vibration
• ?? (Thickness)
• -The thinner, the higher the pitch.
• b. ?? (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)
• c. ??? (Elasticity)
• -The tenser, the higher the pitch.

Superior view of the larynx
(E. Lin)
16
?? ?? (Pitch)
(Ferrand, 2007)
(E. Lin)
17

• 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)
18

• Physical Laws Related to Vocal Fold Vibration
• Equilibrium
• 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

• Three conditions of equllibrium
• (a) unstable, (b) neutral, (c) stable

(Titze, 1994)
(E. Lin)
19

• 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)
20

• 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)
21

• Physical Laws Related to Vocal Fold
  Vibration
• Bernoullis 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)
22

• 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).
• 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)
23
(Titze, 1994)
Coronal section view of the laryngeal system
(E. Lin)
24
Body-Cover Theory
Coronal section through the right vocal fold
(Titze, 1994)
(E. Lin)
25
Mechanically coupling stiffness
Coronal section of vocal fold
(Titze, 1994)
(E. Lin)
26

• Oscillator vocal folds
• Restoring force
• -tissue elasticity
• -airflow/pressure change
• Resting position
• -paramedian position
• (initially prephonatory position)

(Titze, 1994)
(E. Lin)
27

• 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)
28
?? (Resonance) ????????
(Karnell, 1994)
Velopharyngeal port
(E. Lin)
29
?? (Resonance) ??
(Ferrand, 2007)
(E. Lin)
30
?? ??
(Perkins Kent, 1986)
(E. Lin)
31
?? ??
(Perkins Kent, 1986)
(E. Lin)
32
?? ??
(Perkins Kent, 1986)
(E. Lin)
33
?? ??
(Perkins Kent, 1986)
(E. Lin)
34
The Nature of Sound Sound Transmission
(Ferrand, 2007)
(E. Lin)
35
The Nature of Sound Sound Waves
(Ferrand, 2007)
(E. Lin)
36
The Nature of Sound Spectrum
(Ferrand, 2007)
(E. Lin)
37
Source-Filter Theory
Source spectrum
Filter spectrum
Output spectrum
(Titze, 1994)
(E. Lin)
38
Source-Filter Theory Vowel
(Titze, 1994)
(E. Lin)
39
??????? (Speech Voice Measurement)

• Respiratory function
• Airflow
• Muscle movement strength, duration, direction
• Laryngeal function
• 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)
40
????

• Baken, R. J. (1987). Clinical Measurement of
  Speech and Voice. Austin, TX Pro-ed.
• 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)