Applied Speech Sciences
4/11/00
Speech Science Application
• Speech production via computers
• Forensics- criminal investigations; voice prints
• Assessing & treating disorders of communication
Digital Speech Coding
• Speech Synthesis
–Copy Synthesis
–Articulatory Synthesis
–Terminal Analog Synthesis
Copy Synthesis
• Combine smaller elements to form longer
utterances
• Stored patterns include: words, numbers,
syllables
• Connected speech is easy due to the collection of
various suitable patterns
• Difficulties in reading a narrative but works well
with individual numbers (ex. Phone numbers)
Articulatory Synthesis
• Also called transmission-line analog
• Model of the physiology of human speech
– Has articulators (tongue, jaw, lower lip etc.)
– Each is controlled to produce “human-like” speech
• Articulatory synthesizer (Wolfgang von
Kempelen)- bellows (respiratory); vibrating reed
(laryngeal); narrow tubes (vocal tract)
• Modern computer models-Articulatory acoustic
models
Terminal Analog Synthesis
• Attempts to produce satisfactory replicas of the
end product of speech-Acoustic signal
• Do not model speech physiology but depends on
energy sources & resonators- Produce acoustic
patterns like natural speech
• Formant Synthesizer- Specifies formants of a
modeled utterance
• DEC Talk - Formant based synthesizer
Speech, Language & Hearing Disorders
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Voice Disorders
Neurogenic disorders
Structural disorders
Phonological disorders
Fluency disorders
Hearing impairment
Voice Disorders
• Disorders arise from:
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abuse
toxins damaging tissue
benign or cancerous growth
neurological disease
trauma
aging changes
• Voice disorders are estimated to affect 10% of the
population
• School-age- 6-23.4%
Voice Disorders
• Tools used to diagnosis:
– Acoustic & Physiologic techniques to assess status
• Visualization -Videostroboscopy
• Aerodynamic (levels of airflow)
• Acoustic (fundamental, range)
Neurogenic Disorders
• Disorders arise from:
– neurologic disease
– neurologic damage
– neurologic maldevelopment
• Speech disorders:
– Dysarthria (slowness, weakness, incoordinated speech
movements) Affect all 3 speech subsystems
– Apraxia (effects sequence of movements, muscle
weakness is not apparent, slow groping, effortful
articulation)
Neurologic Disorders
• Modern methods of study:
– Acoustic & physiological studies:
• Dysarthria– show relative degree of impairment
– Specific control problems relate to reduced intelligibility
• Apraxia– acoustic studies revealed a variety of sequencing problems
• subtle errors in control of individual movmts.
• Effects several aspects of speech production and is not isolated
to phonemic organization
Structural Disorders
• Abnormalites of physical structures
– Dysmorphology
– Cleft palate
• Disorders occur due to:
– trauma
– surgical procedures
– congenital
Structural Disorders
• Assessment & Management:
– Acoustic - velopharyngeal assessment (nasality)
– Reconstructive surgery
– Aerodynamics (pressure & flow Studies)
Phonological Disorders
• A phonological system that develops more slowly
– Disorders:
• Speech sound errors
• speech-delay
• Assessment & management:
– Used to be mostly perceptual
– Acoustic methods (demonstrates signs that are not
always heard)
Fluency Disorders
• Disorders:
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Part-word
Whole-word
Pauses
Prolongation's
Repetitions
Circumlocution
Fluency Disorders
• Variety of motor, linguistic, psychological and
sociological factors
– Techniques used:
• Acoustic (pause duration etc.)
• Aerodynamic (pressure & flow changes during stuttering
event)
• Respiration (incoordination of breathing measured)