Phonation + Laryngeal Physiology

of 46 /46
Phonation + Laryngeal Physiology January 14, 2010

Embed Size (px)


Phonation + Laryngeal Physiology. January 14, 2010. The Aerodynamics of Speech. Note: all sounds are created by the flow of air Most (but not all) speech sounds are produced by a pulmonic egressive airstream mechanism. = air flows out of the lungs. - PowerPoint PPT Presentation

Transcript of Phonation + Laryngeal Physiology

Page 1: Phonation +  Laryngeal Physiology

Phonation + Laryngeal Physiology

January 14, 2010

Page 2: Phonation +  Laryngeal Physiology

The Aerodynamics of Speech• Note: all sounds are created by the flow of air

• Most (but not all) speech sounds are produced by a pulmonic egressive airstream mechanism.

• = air flows out of the lungs

• Note: air flows naturally out of the lungs when they are compressed

• air always flows from areas of high pressure to low

Page 3: Phonation +  Laryngeal Physiology

Lung Compression• In speech, lung compression is typically a passive process.

• The linkage between the lungs and the thoracic (rib) cage tends toward an equilibrium--

• at which the lungs are larger than they would be alone…

• and the rib cage is smaller than it would be alone.

• When the linked pair is expanded beyond the equilibrium point, it will naturally contract back to it.

• (and vice versa)

Page 4: Phonation +  Laryngeal Physiology

Lung Expansion• The expansion of the lungs is primarily driven by the contraction of the muscles in the diaphragm.

• This increases volume in the vertical dimension.

• Contraction of the external intercostal muscles also pulls out the rib cage in the front-back and side-to-side dimensions.

• intercostal = “between the ribs”

Page 5: Phonation +  Laryngeal Physiology

Riding the Wave• Speech is normally produced on the passive expiration that follows an expansion of the lungs.

• Airflow may be fine-tuned by contraction of the internal intercostal muscles.

• Active contraction results in:

• higher airflow

• higher intensity

• greater perceived stress

Page 6: Phonation +  Laryngeal Physiology

Back to Aerodynamics• Remember: sounds are created by the flow of air

• …but speech often becomes interesting when that flow of air is interrupted.

• E.g., aerodynamic method #1: Stops

A. start air flow

B. stop air flow

C. release air flow

• Here’s an example of aerodynamic method #2.

• What kind of sound was that?

Page 7: Phonation +  Laryngeal Physiology

Trills• A: a Trill. A Bilabial Trill:

• Examples from Kele and Titan (spoken on the island of Manus, north of New Guinea)

Page 8: Phonation +  Laryngeal Physiology

Any volunteers?• Does anyone else know how to produce a bilabial trill?

• And would anyone like to demonstrate?

• How fast do your lips open and close when you make a bilabial trill?

• Let’s take a look at the waveform in Praat…

• Waveform = representation of the change in air pressure over time.

Page 9: Phonation +  Laryngeal Physiology

Some Terminology• Frequency is the rate at which the lips are opening and closing

• measured in Hertz (cycles per second)

• Period is the length of time between cycles

• Frequency = 1 / Period

• Some questions:

• In a bilabial trill, do we close and relax our lips on each cycle?

• When air blows the lips apart, why don’t they stay apart?

Page 10: Phonation +  Laryngeal Physiology

Bernoulli Effect• In a flowing stream of particles:

• the pressure exerted by the particles is inversely proportional to their velocity

• Pressure = constant


• P = k / v

• the higher the velocity, the lower the pressure

• the lower the velocity, the higher the pressure

Daniel Bernoulli


Page 11: Phonation +  Laryngeal Physiology

Bernoulli Examples

• Airplane wing

• Shower curtain

• Pieces of paper

• Bilabial trills!

Page 12: Phonation +  Laryngeal Physiology

A Trilling Schematic• Lips are closed

• adducted = brought together

• Fad = adductive force

upper lip

lower lip

inside of mouth

outside of mouth



Page 13: Phonation +  Laryngeal Physiology

Trilling: Stage 1• Pressure builds up inside mouth from compression of lungs

• Pin = Air Pressure inside mouth

• Outside pressure remains constant

• Pout = Air Pressure outside mouth

PinPout = k



Page 14: Phonation +  Laryngeal Physiology

Trilling: Stage 1• Pressure differential between inside and outside builds up

• This exerts force against the lips

PinPout = k



P = (Pin - Pout )

Page 15: Phonation +  Laryngeal Physiology

Trilling: Stage 2• Pressure differential blows open lips

• Air rushes from high to low pressure

PinPout = k




Page 16: Phonation +  Laryngeal Physiology

Trilling: Stage 2• The opening of the lips means:

1. P decreases slightly

2. High velocity of air flowing between lips

3. Air pressure decreases between lips (Bernoulli Effect)

PinPout = k




Page 17: Phonation +  Laryngeal Physiology

Trilling: Stage 3• Lips get sucked back together

PinPout = k



Page 18: Phonation +  Laryngeal Physiology

Trilling: Back to Stage 1• If air is still flowing out of lungs, pressure will rise again

within mouth

• Process will repeat itself as long as air is pushed up from lungs and lips are held lightly against each other

PinPout = k



Page 19: Phonation +  Laryngeal Physiology

Trilling: Back to Stage 1• Air rushes through the lips in a series of short, regular





Page 20: Phonation +  Laryngeal Physiology

Trill Places

Page 21: Phonation +  Laryngeal Physiology

Phonation• Glottal trilling is known as phonation.

• It distinguishes between voiced and voiceless sounds.

• [z] vs. [s]; [v] vs. [f], etc.

• Glottal trilling is made possible by the presence of two “vocal folds” within a complicated structure known as the larynx.

• When the vocal folds are:

1. open: air passes cleanly through (= voiceless sound)

2. closed: air does not pass through (= no sound)

3. lightly brought together: vocal folds vibrate in passing air

(= voiced sound)

Page 22: Phonation +  Laryngeal Physiology

Voicing, Schematized

Voiceless (folds open) Voiced (folds together)

(= “abducted”) (= “adducted”)

Page 23: Phonation +  Laryngeal Physiology



Page 24: Phonation +  Laryngeal Physiology

Voicing, in Reality

Page 25: Phonation +  Laryngeal Physiology

Creaky Voicing• The flow of air from the lungs forces the vocal folds to open and close.

• The slowest type of voicing is called “creaky voice.”

Page 26: Phonation +  Laryngeal Physiology

Modal Voice

• How fast do you think the vocal folds open and close in normal voicing?

• In normal, or “modal” voicing, the rate of glottal trilling is considerably faster.

Page 27: Phonation +  Laryngeal Physiology

Vocal Fold Specs• In bilabial trills, lips open and close 20-25 times a second

• In modal voicing, the glottal trill cycle recurs, on average:

• 120 times a second for men

• 220 times a second for women

• 300+ times a second for children

• For voiced speech sounds, this rate is known as the fundamental frequency (F0) of the sound.

• Let’s check it out…

Page 28: Phonation +  Laryngeal Physiology

Vocal Fold Specs• Air rushes through vocal folds at 20 to 50 meters per second

• = between 72 and 180 kph (45 ~ 120 mph)

• Due to Bernoulli Effect, pressure between vocal folds when this occurs is very small

• Speed of “glottal trill” cycle depends on:

• thickness of vocal folds

• tenseness of vocal folds

• length of vocal folds

Page 29: Phonation +  Laryngeal Physiology

Vocal Fold Specs• In men, vocal folds are 17-23 millimeters long

• In women, vocal folds are 12-17 millimeters long

• Adult male vocal folds are 2-5 millimeters thick

• Adult female vocal folds are slightly thinner

• Thicker, longer folds vibrate more slowly

• Think: violin strings vs. bass strings

• Tenseness of vocal folds can be changed to alter the speed of glottal opening and closing.

• Like tuning a violin or a guitar…

Page 30: Phonation +  Laryngeal Physiology

The Larynx• The larynx is a complex structure consisting of muscles, ligaments and three primary cartilages.

Page 31: Phonation +  Laryngeal Physiology

1. The Cricoid Cartilage• The cricoid cartilage sits on top of the trachea

• from Greek krikos “ring”

• It has “facets” which connect it to the thyroid and arytenoid cartilages.

cricoid cartilage

Page 32: Phonation +  Laryngeal Physiology

2. The Thyroid Cartilage• The thyroid cartilage sits on top of the cricoid cartilage.

• from the Greek thyreos “shield”

• The thyroid cartilage has horns!

• Both lower (inferior) and upper (superior) horns

• The lower horns connect with the cricoid cartilage at the cricoid’s lower facet.

• The upper horns connect to the hyoid bone.

Page 33: Phonation +  Laryngeal Physiology

Thyroid Graphic

thyroid cartilage

cricoid cartilage

Page 34: Phonation +  Laryngeal Physiology

Thyroid Angles• The two broad, flat front plates of the thyroid--the laminae--meet at the thyroid angle.

• The actual angle of the thyroid angle is more obtuse in women.

• the “Adam’s Apple” juts out more in men.

Page 35: Phonation +  Laryngeal Physiology

3. The Arytenoid Cartilages• There are two arytenoid cartilages.

• from Greek arytaina, “ladle”

• They are small and pointy, and sit on top of the back side, or lamina, of the cricoid cartilage.

arytenoid cartilages

cricoid cartilage

Page 36: Phonation +  Laryngeal Physiology

The Vocal Folds• These three cartilages are connected by a variety of muscles and ligaments.

• The most important of these are the vocal folds.

• They live at the very top of the trachea, in between the cricoid and thyroid cartilages.

• The vocal folds are a combination of:

• The vocalis muscle

• The vocal ligament

• The vocal folds are enclosed in a membrane called the conus elasticus.

Page 37: Phonation +  Laryngeal Physiology

• Just above the true vocal folds are the “false” (!) vocal folds, or ventricular folds.

• The space between the vocal folds is the glottis.

Vocal Fold View #1

Page 38: Phonation +  Laryngeal Physiology

Vocal Fold View #2• The vocal ligaments attach in the front to the thyroid cartilage.

• ...and in the back to the arytenoid cartilages.

• The glottis consists of:

• the ligamental glottis

• the cartilaginous glottis

Page 39: Phonation +  Laryngeal Physiology

Things Start to Happen• Note that the arytenoid cartilages can be moved with respect to the cricoid cartilage in two ways.

#1: rocking #2: sliding

Page 40: Phonation +  Laryngeal Physiology

The Upshot• The arytenoids can thus be brought together towards the midline of the body.

• Or brought forwards, towards the front of the thyroid.

• The rocking motion thus abducts or adducts the glottis.

• The sliding motion shortens or lengthens the vocal folds.• Check out the arytenoids in action.

Page 41: Phonation +  Laryngeal Physiology

• When the vocal folds are abducted:

• air passes through the glottis unimpeded and voicelessness results.

• The posterior cricoarytenoid muscles are primarily responsible for separating the arytenoid cartilages.

Page 42: Phonation +  Laryngeal Physiology

• Voicing may occur when the vocal folds are adducted and air is flowing up through the trachea from the lungs.

• Two muscles are primarily responsible for adducting the vocal folds.

• The first is the lateral crico-arytenoid muscle.

Page 43: Phonation +  Laryngeal Physiology

• Note that the lateral cricoarytenoid muscles only adduct the ligamental glottis.

• The transverse arytenoid muscles pull together the arytenoid cartilages themselves.

• Thereby closing the cartilaginous glottis.

Page 44: Phonation +  Laryngeal Physiology

The Consequences• The combined forces drawing the vocal folds towards each other produce adductive tension in the glottis.

• Adductive tension is increased by:

• lateral cricoarytenoid muscles

• transverse arytenoid muscles

• Adductive tension is decreased by:

• posterior cricoarytenoid muscles

• Adduction vs. abduction determines whether or not voicing will occur.

• But we can do more than just adduce or abduce the vocal folds...

Page 45: Phonation +  Laryngeal Physiology

Factor Two

• We can also change the longitudinal tension of the vocal folds.

• I.e., tension along their length, between the thyroid and arytenoid cartilages.

• Higher tension = higher F0

• Lower tension = lower F0

• Q: How is this possible?

Page 46: Phonation +  Laryngeal Physiology

• A: We can rotate the thyroid cartilage up and down on its connection with the cricoid cartilage.

• the visor of a knight’s helmet.

• This either stretches or relaxes the vocal folds.