Speech Production Process

4 Processes in Speech Production Respiration Phonation Resonance Articulation

Respiration: Power Mechanism Provides the energy for sound Breathing is an aerodynamic process a difference in air pressure is created between the thoracic cavity and the atmospheric pressure outside the body

2 Phases of Breathing Inhalation - muscles of the thoracic cavity expand the chest; air pressure decreases and air is taken in air pressure is less in thorax than in atmosphere and air flows in Exhalation - when the pressure is greater in thorax, air flows out there is a decrease in chest cavity and an increase in air pressure

Breathing for Speech vs Breathing for Life Breathing for speech uses same muscles, but is controlled more exhalation phase is longer than inhalation phase for speech Breathing for life, inhalation and exhalation phases are same

Phonation: Vibrating Mechanism Phonation is the rapid opening and closing of the vocal folds for sound the vocal folds lie horizontally in the larynx they attach anteriorly to the thyroid cartilage and posteriorly to the artynoid cartilages; they are free in the middle the opening in the middle of the vocal folds is the GLOTTIS

Phonation (con’t) adduction of the arytnoids closes the vocal folds the middle of the vocal folds vibrate to and from midline vibration of the vocal folds produces voicing Position of vocal folds open (abducted) closed (adducted)

3 major aspects of voice influenced by vocal fold movement Pitch - frequency of vibration the rate of vocal fold vibration is called the FUNDAMENTAL FREQUENCY this is measured in terms of Hz or cps therefore, if the vocal folds vibrate 200 cps it is a fundamental frequency of 200Hz an increase in pitch involves an increase in frequency (hi pitch; hi frequency) the frequency of vocal fold vibration depends on the mass and length of the vocal folds and the tension

3 major aspects (con’t) Loudness - intensity of sound involves the amount of energy generated by the vocal fold movements intensity increases with increased air pressure from the lungs and increased amplitude of the vocal fold vibration Quality - the sound quality of the voice this is affected by the pattern of movement of the vocal folds

Resonance: The characteristic quality of the voice The speech mechanism is a resonator -- it is like an air-filled tube (closed on one end and open at the other end) the fundamental frequency generated at the vocal folds is resonated in the vocal tract that is now also vibrating -- the vibration of the vocal tract is the HARMONIC FREQUENCY every body or object has its own natural frequency those frequencies that match the vocal tract’s natural frequency will be amplified this is resonance

Resonance (con’t) Pharynx is the primary resonator recall the 3 parts of the pharynx (nasopharynx, oropharynx, laryngopharynx) the nasopharynx and oropharynx are the 2 resonating systems these 2 systems provide resonance to sounds that pass through the oral and nasal cavities

Articulation Serves to produce the different configurations which make up the different speech sounds

Dynamics of Speech Production Speech is a dynamic rather than a static phenomenon the articulators are in a state of constant movement during speech Individual speech sounds are described in terms of target positions; ongoing speech is better thought of in terms of movement

Dynamics of Speech Production (con’t) Sounds in a word don’t follow each other like printed letters spoken sounds overlap with each other this is referred to as CO-ARTICULATION

Co-articulation as the articulators are in the process of forming one sound, their positioning prepares them for the sound that follows speech sounds influence and are influenced by other sounds within a phonetic environment the dynamic nature of speech means that we are planning events before they occur we may articulate one segment before completing another we may be as much as several segments ahead or behind in our motor activity

Co-articulation Important clinically because a client cannot simply be taught to pronounce a given sound in one simple way need to provide practice in a variety of phonetic environments Examples of co-articulation /iki/ - point of artic for /k/ is more forward (palatal) than velar / uku/ - point of artic for /k/ is more posterior (uvular) than velar /aka/ - point of artic for /k/ is actually velar sneeze ~ snooze; see ~ Sue

Co-articulation (con’t) Why do we have co-articulation? It’s not because we’re lazy. There are too many demands on the speech mechanism than there is time to fulfill them normal conversation is produced at a rate of between 10-20 segments/second which implies a maximum of 100msec/segment however, it takes much longer than this to complete any speech gesture and then return to the starting point THEREFORE, something has to give -- thus, compromise gestures are made

Co-articulation (con’t) It is true that dialects and registers of speech (formal vs informal) differ in the amount of coarticulation that can be made non-native speakers want to learn this allowable accommodations in order to sound more normal the second language learner often has a hypercorrect pronunciation that sounds strange because it lacks the usual shortcuts that native speakers take Need to distinguish co-articulation from assimilation co-articulation means that 2 different sounds were being articulated simultaneously one tongue movement was made for both sounds

Assimilation Refers to changes that cross phonemic boundaries and results in a major phonetic change The resulting change is to a different sound (phoneme) Co-articulation results in non-phonemic differences In assimilation, there is a major change in the place of articulation, manner of articulation, or voicing of a segment, such that it falls into a different phonemic category Examples of assimilation I miss you; got you; had you; phone booth

Types of Assimilation (direction of accommodation) Regression assimilation - a particular sound influences the sound immediately preceding it EX: miss you also referred to anticipatory, or right-to-left assimilation Progressive assimilation - a given sound produces changes in the sound that follows EX: cats dogs left-to-right assimilation

Other Combinatory Phenomena Elision (ellipsis) - when a segment or several segments are left out of a word when it is pronounced dialectal differences in elision, e.g., “interesting”, “secretary” Epenthesis - the insertion of a sound, generally to break up consonant clusters or to provide a transition between sounds

Other Combinatory Phenomena (con’t) Metathesis - when two adjacent segments are reversed EX: “ask” [æks] dialectal metathesis