Respiratory Physiology

Breathing For Speech

• Air under pressure

• Air pressure forces vocal folds apart

• To achieve pressure it requires air flow

to be resisted

Pressure Requirements: Loudness

• Produce a soft tone followed by a loud tone:

– Observe the increased pressure needed to increase

loudness

• For speech: resist the flow of air just enough to

produce the desired sound

• How do you achieve the necessary pressure for

speech?

– Adjusting the expiratory force of the resp. pump

– Adjusting airway resistance

Pressure Requirements: Speech

• Adjusting expiratory pressure & airway resistance:– Both necessary to generate pressure

– Affect air reservoir in lungs- Alveolar pressure

– Resulting pressure build up in trachea under folds- Subglottal Pressure

• Variations in airway resistance to expiratory forces determine pressure

Respiratory PressuresExpiratory Force

PressureIncreases

AlveolarPressure

TrachealPressure

Low Pressure High Pressure

Stress & Articulation• Speech is dynamic (not monotone)

– need more than steady resp. alveolar pressure

– Stress varies syllable to syllable

– Stress variations made by adjustments in:

• Pitch

• Loudness

• Duration

Stress & Articulation• Loudness of syllable= Varies with changes

in alveolar pressure (small muscle contractions)

• Intensity varies from sound to sound

• Vowels more intense than consonants

• Sound intensity controlled by changes to airway resistance that alter intraoral pressure– Example: “Too” - Pressure rises for “t”

Pressure Requirements & Durations

Loudness (Phrase)

Stress (Syllable)

Phonetic Intensity(Phone)

Volume Requirements

• Speech breathing differs from quiet respiration:

– Requires greater volumes

• Quiet (10-15% of VC)

• Conversational (25% of VC)

• Loud Speech (40% of VC)

• Differences achieved by the amount of air inhaled above resting volume

Volume Requirements

0

40

100

RestingTidal

Volume

ConversationalTidal

Volume

LoudTidal

Volume

Resting volume

40% of VC

55% of VC

60-65% of VC

80-85% of VC

Frequency Requirements• Breathing frequency- 10-20 times per minute

• Length of breath depends on length of utterance

• Grunting “Uh-huh” will take longer than quiet breathing

• Loud statement requires deep inspiration of air which we use past resting (forced expiration)

• Usually loud utterance not past 35% VC

Frequency Requirements

0

40

100

RestingVolume

“UH HUH”

80%

Impassioned Plea

35%

% V

C

Duration Requirements

• Different between quiet & speech:– How quickly we inhale– Resting or heavy exercise- inhale= exhale– Production of sound (whisper, argue, sing or

converse)= quick inhalation & long, slow exhalation– Speech: 10% of respiratory cycle (inhaling); 90%

(exhaling)

• Duration during speech depends on:– Breathy– Loudness

Duration Requirements%

VC

Inspiration Expiration

10% 90%

RestingVolume

Conversation Loud Breathy

Respiratory Mechanics of Speech

• What adaptations to the respiratory

system are made for speech?

– Control over:

• 1) Effects of changes in lung volume during the

phrase

• 2) Active expiratory forces needed to maintain

required alveolar pressure for the phrase

Relaxation Pressure & Lung Volume

• Deeper the inspiration = greater resistance of elastic lung tissue & air sacs against greater stretching & inflation

• Relaxation Pressure (Passive expiratory force) = Elastic recoil from inspiration, gravity & untorquing of rib cartilage when chest is raised

Relaxation Pressure & Lung Volume

• Louder & longer the phrase= Greater volume

of air (volume & depth of inspiration

increase)

• Inspiration increases= Passive resistance

recoil increases= Greater relaxation pressure

• Elastic recoil are so strong that they exceed

alveolar pressure for speech (above 60%)

Speech Pressures & Volumes

Tidal Volume% V

CR

elax

atio

np

ress

ure

Atmospheric pressure

Atmospheric pressure

Alveolar Pressurefor Speech

Maintaining Alveolar Pressure for Speech• Both inspiratory & expiratory muscles are used to

begin to speak

• Some expiratory muscles are used during inspiration

• When you begin to speak:

– Relaxation pressures too high for the alveolar pressure

– Offset excessive relaxation pressure by inhalatory muscular contraction continuing to lift the rib cage until relaxation pressure was reduced to the necessary alveolar pressure

Respiratory Dynamics for Speech

Relaxation PressureAtmosphericPressure

Alveolar Pressure for Speech

Expiratory Contraction Increases

Active Inspiratory Checking ofRelaxation Pressure Increases

Reading/Assignments

• Seikel: Pgs. 135-153

• Dickson: Pgs. 85-87