1. Speech Perception
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2. Basic Issues in Speech Perception
Speaker Normalization
Time Normalization
Integration: Segmental & Suprasegmental Information
Defining Units of Speech Perception
Cross-Modal Aspects of Speech Perception

3. Speaker Normalization
Normalization needed because of differences in acoustic measures of speech
Women & men are biologically and acoustically different
How do we perceive these differences?
This perception is present in infants:
Can recognize the same phonetic element produced by a woman or a man
Word recognition performance is poorer for words from a mixed group of talkers than for words produced by a single talker
Conclusion: Listeners make adjustments for different talkers

4. Speech: 4 Types of Information
Phonetic Quality
Linguistic content
Affective Quality
Paralinguistic emotional quality that accomplishes the linguistic message
Personal Quality
Extralinguistic information about the talker but not the message
Transmittal Quality
Perspectaval information about the talkers location, including distance between talker & listener, orientation is space & presence of background noise

5. Time Normalization
Different talkers speak at different rates & different rates at different times
Speaking rates vary because segment durations are flexible
Variable acceptance of different duration VOT
Is speech intelligibility reduced for speakers who deviate from typical temporal patterns of normal adult speech?
Children & disordered speech

6. Integrating Segmental & Suprasegmental Information
Suprasegmental cues (intonation, rhythm, & pausing) help the listener segment the incoming message
How is suprasegmental information used with segmental information?
Acoustic cues (f0, duration & intensity) signal suprasegmental structure such as stress & rhythm

7. What is the Basic Unit of Perception?
When we listen to speech, do we analyze it in terms of features, phonemes, syllables or words?
Listeners of different ages and linguistic competence prefer different size units
Young children operate with syllable-sized units
Adults extract phoneme level information

8. Cross-Model Speech Perception
Do listeners with normal hearing attend to visual cues in speech?
McGurk effect: This effect was produced by studying different combinations of visual and auditory cues
ex. subjects would view a video tape of a speaker saying the syllable [ba], but would hear the acoustic signal [da]
Subjects identified the sound as [g]: Phonetic decision was based on a synthesis of auditory & visual cues

9. Speech Perception: Infancy & Childhood
We hear in the womb
Early auditory experiences biases the neonate to the mother’s voice
By the 1st year, infants can specialize sounds of the mother tongue
By this age they have lost discrimination for foreign sounds
Auditory reorganization
Children continue to improve basic discrimination of frequency, intensity & duration until age 7 years

10. Speech Perception, Language, Learning & Education
Children are less able to discriminate speech in noisy or reverberant environments
Children are more prone to some diseases that disrupt speech perception
Otitis Media
ex. may not recognize VOT variation (history of ear infections)

11. Speech Perception, Language, Learning & Education
Speech perception difficulties contribute to language disorders in children-
Certain grammatical morphemes in English have low “phonetic substance”
ex. “s” in dogs or past tense marker in talked
These morphemes are harder to hear & are difficult to perceive

12. Speech Perception, Language, Learning & Education
Speech perception and classroom learning-
Environment not ideal:
teacher’s speech about 6 dB more intense than background noise
Teacher turning head away from listener
Typical classroom has a reverberation time of 0.45 seconds
Distance of teacher to student
ex. % of words heard by 5- to 7- year old children with normal hearing with varied distance
89% at 6 feet
55% at 12 feet
36% at 24 feet