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 Pressures
Expiratory Force
Pressure
Increases
Tracheal
Pressure
Alveolar
Pressure
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
100
80-85% of VC
60-65% of VC
Resting
volume
40% of VC
40
0
55% of VC
Resting Conversational Loud
Tidal
Tidal
Tidal
Volume
Volume
Volume
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
100
% VC
80%
40
Resting
Volume
Impassioned Plea
“UH HUH”
0
35%
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
Inspiration
Expiration
90%
% VC
10%
Resting
Volume
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%)
Relaxation
pressure
% VC
Speech Pressures & Volumes
Atmospheric pressure
Alveolar Pressure
for Speech
Atmospheric pressure
Tidal Volume
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
Atmospheric
Pressure
Alveolar Pressure
for Speech
Expiratory Contraction Increases
Active Inspiratory Checking of
Relaxation Pressure Increases
Reading/Assignments
• Seikel: Pgs. 135-153
• Dickson: Pgs. 85-87