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, TaiwanDecember 2, 2006

• 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)

大綱

口語溝通通路

(E. Lin)(Perkins & Kent, 1986)

(E. Lin)

言語系統

(Perkins & Kent, 1986)

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)

(E. Lin)

(Perkins & Kent, 1986)

anteroposterior

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

(E. Lin)(Perkins & Kent, 1986)

(E. Lin)

呼吸 : 可能影響呼吸的病症

(Ferrand, 2007)

Endoscopic view of the larynx

(E. Lin)

發聲 : 聲帶

(Karnell, 1994)

Normal inhalation

Forced exhalation

Forced inhalation

發聲 : 呼吸和聲門 (glottis) 大小的關係

(E. Lin)

(Zemlin, 1968, 1988)

(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)

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)

c. 彈性度 (Elasticity)-The tenser, the higher the pitch.

Superior view of the larynx

(E. Lin)

發聲 : 音頻 (Pitch)

(E. Lin)

(Ferrand, 2007)

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

(E. Lin)

(Titze, 1994)

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

(E. Lin)

(Titze, 1994)

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)

(E. Lin)(Titze, 1994)

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: flowv: velocityA: area

(E. Lin)(Titze, 1994)

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 + 0.5v2 = constant)

P: pressure (force per unit area; e.g., the force exerted on the surface of the duct): fluid densityv: fluid velocity

If the energy is constant, then as velocity increases,

pressure decreases.

(E. Lin)(Perkins & Kent, 1986)

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).

1. Vocal folds move together. (active tissue movement)2. Narrow constriction in the glottis leads to increased velocity, thus

decreased pressure. (fluid flow)3. Vocal folds are further sucked together by negative Bernoulli

pressure in the glottis. (fluid induced tissue inward movement)4. Vocal fold closure leads to buildup of subglottal pressure, forcing

the folds to open. (fluid induced tissue outward movement)5. Lateral (opening) movement continues till elastic forces in the

tissue retard the movement and reverse it. (tissue recoiling)

(E. Lin)

Coronal section view of the laryngeal system(E. Lin)

(Titze, 1994)

Coronal section

through the right vocal

fold

(E. Lin)

(Titze, 1994)

Body-Cover Theory

Mechanically coupling stiffness

Coronal section of vocal fold

(E. Lin)

(Titze, 1994)

• Oscillator: vocal folds• Restoring force:

-tissue elasticity-airflow/pressure change

• Resting position: -paramedian position(initially: prephonatory position)

(E. Lin)

(Titze, 1994)

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)

Velopharyngeal port(E. Lin)

共鳴 (Resonance): 口腔和鼻腔的分隔

(Karnell, 1994)

共鳴 (Resonance): 鼻音

(E. Lin)

(Ferrand, 2007)

(E. Lin)

發音 : 聲腔

(Perkins & Kent, 1986)

(E. Lin)

(Perkins & Kent, 1986)

發音 : 聲腔

(E. Lin)(Perkins & Kent, 1986)

發音 : 母音

(E. Lin)(Perkins & Kent, 1986)

發音 : 子音

(E. Lin)

The Nature of Sound: Sound Transmission

(Ferrand, 2007)

(E. Lin)

The Nature of Sound: Sound Waves

(Ferrand, 2007)

(E. Lin)(Ferrand, 2007)

The Nature of Sound: Spectrum

Source spectrum

Filterspectrum

Outputspectrum

(E. Lin)

Source-Filter Theory

(Titze, 1994)

(E. Lin)

Source-Filter Theory: Vowel

(Titze, 1994)

語音和音聲測量 (Speech & Voice Measurement)

(E. Lin)

• 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

參考文獻1. Baken, R. J. (1987). Clinical Measurement of Speech and Voice. Austin, TX:

Pro-ed.2. Bernthal, J. E. & Bankson, N. W. (1988). Articulation and Phonological

Disorders, 2nd ed. Englewood Cliffs, NJ: Prentice Hall.3. Ferrand, C. T. (2007). Speech Science: An Integrated Approach to Theory and

Clinical Practice, 2nd ed. Boston: Allyn & Bacon. 4. Karnell, M. P. (1994). Videoendoscopy: From Velopharynx to Larynx. San

Diego: Singular Publishing.5. Perkins, W. H. & Kent, R. D. (1986). Functional Anatomy of Speech, Language,

and Hearing. Boston: Allyn & Bacon.6. Pickett, J. M. (1999). The Acoustics of Speech Communication: Fundamentals,

Speech Perception Theory, and Technology. Boston: Allyn & Bacon.7. Titze, I. R. (1994). Principles of Voice Production. Englewood Cliffs, NJ:

Prentice Hall.

(E. Lin)