final review - speech perception / prosody

speech science final !

What is categorical speech perception?

The brain classifies sounds into distinct phonemic categories with sharp boundaries and no gradual blending.

What is the difference between active and passive theories of speech perception?

Active theories involve the listener’s knowledge and cognitive processes, while passive theories suggest perception is primarily sensory and relies on acoustics.

What is middle ear impedance mismatch?

The challenge of transferring sound from air (low impedance) to fluid-filled cochlea (high impedance). The middle ear compensates for this.

What does the ear canal act as in hearing?

An amplifier.

How does the middle ear overcome the impedance mismatch between air and fluid?

By increasing sound pressure level by 30 dB using three mechanisms.

What are the three mechanisms the middle ear uses to amplify sound?

The three mechanisms are:

• the area ratio of the tympanic membrane to the stapes footplate

• the lever and crowbar action of the ossicles

• the curvature of the tympanic membrane

How does speech production use auditory feedback?

We listen to our own speech to monitor and adjust articulation and accuracy.

negative feedback

Feedback that requires no change in performance.

positive feedback

Feedback that requires change in performance.

Closed loop system

performance of system considers feedback

Open loop system

performance of system does not consider feedback.

What sensory systems are used for speech feedback?

Auditory, tactile, and proprioceptive systems.

How are the sensory systems are used for speech feedback?

• Auditory - hearing your own voice to make sure you're saying words correctly

• Tactile - feeling articulatory movements while you speak

• Proprioceptive - awareness of of position and movement of articulators

f2 transitions

changes in second formant frequencies during a consonant-vowel transition that help distinguish between different sounds.

voice onset time

time between release of a stop consonant and the onset of vocal fold vibration

• longer than 30 msecs = voiced sound

• shorter than 30 msecs = voiceless sound

air conduction

Transmission of sound through the air via the outer and middle ear to the inner ear

bone conduction

Sound bypasses the outer and middle ear, traveling directly through the skull bones to the cochlea.

features that help us perceive speech

pitch, amplitude, duration, VOT, F2 transition

What can you observe about vowels and consonants on a spectrograph?

Vowels show steady formants; consonants show rapid transitions and noise patterns (for fricatives/stops).

acoustics characteristics of stress

• higher f₀

• greater intensity

• longer duration

juncture

the way boundaries between words or syllables are segmented in speech (separation of syllables and word boundaries)

toneme

a phoneme in which the tone can change the meaning