Problem 9 - DONE

Question 1

how do we produce sounds?

Answer 1

1. lungs: respiration
2. vocal tract: articulation
   - -> oral tract + nasal tract
3. vocal folds: phonation/voicing/fundamental frequencies of speech
   - -> larynx

Question 2

speech sounds

Answer 2

= produced by position/movement of structures within vocal apparatus which produce acoustic signal (= pressure changes in air)

1. air is pushed up from lungs
2. past vocal cords
3. into vocal tract
   - shape of vocal tract: altered by moving articulators (= structures such as tongue, lips, teeth, jaw)
   - -> articulation

Question 3

production of vowels

Answer 3

• by vibration of vocal cords
• -> specific sounds of vowels: by changing overall shape of vocal tract
  1. change in shape
  2. changes resonant frequency of vocal tract
  3. produces formants
• formants = frequencies at which peaks occur (first formant F1: lowest frequency; second formant F2: the next highest…)
• -> each vowel sound: characteristic series of formants

Question 4

sound spectrogram

Answer 4

= three-dimensional display;

• -> horizontal axis: time
• -> vertical axis: frequency
• -> colour: amplitude (intensity) (redder = greater intensity/ grey scale)
• -> indicates pattern of frequencies and intensities over time that make up the acoustic signal

Question 5

production of consonants

Answer 5

• by constriction/closing of the vocal tract
• -> movements of articulators: create patterns of energy in acoustic signal
• formant transitions = rapid shifts in frequency preceding/following formats
• -> associated with consonants

Question 6

phonation

Answer 6

= vocal folds are made to vibrate when air pushes out of lungs

Question 7

articulation

Answer 7

= shape of vocal tract is altered by moving articulators

Question 8

resonant frequency/characteristics

Answer 8

= changing size and shape of space through which sound passes increases/decreases energy at different frequencies

Question 9

frequency spectra

Answer 9

= represents sounds that do not vary over time

Question 10

phoneme

Answer 10

= shortest segment of speech

• change phoneme: change meaning of word
• number of phonemes: varies across languages
• number of vowels: greater than vowel letters, because of different pronunciation
• phonemes form –> syllables –> form words

Question 11

variability problem

Answer 11

= variable relationship between acoustic signal and sound we hear

• -> particular sound can be associated with number of different acoustic signals
• variability from context
• variability from different speaker

Question 12

variability form context

Answer 12

• -> context in which phoneme occurs influences acoustic signal
• coarticulation = overlap between articulation of neighbouring phonemes
• -> perceptual constancy: we perceive sound of phoneme as same even though acoustic signal is changed by coarticulation

Question 13

variability of different speakers

Answer 13

• -> different speakers pronounce in different ways
• individual differences: pitch of voice, pace of speaking
• sloppy pronunciation: not articulate each word individually

Question 14

solutions for variability problem

Answer 14

• categorical perception
• information from facial expression
• information from our knowledge of language

Question 15

categorical perception

Answer 15

= occurs when stimuli that exist along a continuum are perceived as divided into discrete categories
{- vision: along the visible spectrum = five categories}
- speech: continuum = voice onset time (VOT)
–> voice onset time (VOT) = time delay between when a sound begins and when the vocal cords begin vibrating
–> phonetic boundary = VOT when the perception changes from one category to the next
=> even though the VOT is changed continuously listener perceives only two categories: /da/ on one side of the phonetic boundary and /ta/ on the other side
–> perceptual constancy: all stimuli on same side of the phonetic boundary are perceived as the same category

Question 16

information provided by the face

Answer 16

• speech perception = multimodal: can be influenced by number of different senses
• audiovisual speech perception = influence of vision on speech perception
  => auditory information: major source of information; visual information: strong influence on what we hear

Question 17

McGurk effect

Answer 17

–> hears sounds /ba-ba/, when visual stimulation is added showing person making the lip movements for the sound /ga-ga/, listener begins hearing the sound /da-da/

Question 18

information from our knowledge of language

Answer 18

• -> easier to perceive phonemes that appear in meaningful context
• phonemic restorations effect = sounds missing from speech can be restored by the brain and appear to be heard
• -> speech perception can be determined by:
• bottom-up processing: nature of acoustic signal
• top-down processing: context that produces expectations in listener
• -> can be influenced by meaning of words following missing phoneme

Question 19

perceiving words in incomplete sentences

Answer 19

• -> words/sentences can be read even if incomplete
• familiarity with language of the present sentence
• -> knowledge of rules (grammar)
• meaningfulness makes it easier to perceive spoken words

Question 20

speech segmentation

Answer 20

= perception of individual words in a conversation
- not only based on energy stimulating the receptors –> knowledge of meanings of words + use of context in which these words occur

Question 21

transitional probabilities

Answer 21

= ways sounds follow one another in a language; chances that one sound will follow another sound

• -> certain sounds are more likely to follow one another within a word + other words are more likely to be separated by the space between two words
• -> statistical learning = process of learning about transitional probabilities and about other characteristics of language

Question 22

characteristics of speaker

Answer 22

indexical characteristics = characteristics that carry information about speaker (age, gender, place of origin, emotional state, whether they are being sarcastic or serious)

• speaker’s tone of voice
• speaker’s identify

Question 23

speech perception

Answer 23

depends on:

• bottom-up information: acoustic signal
• top-down information: meanings of words/sentences, listener’s knowledge of the rules of grammar, information listener has about characteristics of speaker’s voice

Question 24

cortical locations of speech perception

Answer 24

• Broca’s area: in the frontal lobe
• Wernicke’s area: in the temporal lobe
• voice area: superior temporal sulcus (STS)
• -> activated by human voices
• -> voice cells = temporal lobe; respond to voice sounds

Question 25

brain damage and speech perception

Answer 25

• aphasia = language problem caused by damage to specific areas in the brain
• -> symptoms: depending on area damaged + extent of damage
  (1) Broca’s aphasia = laboured and stilted speech, can only speak in short sentence; capable of comprehending what others are saying
  (2) Wernicke’s aphasia = speak fluently, but what they say is extremely disorganised and not meaningful; great difficulty understanding what other people are saying
• -> most extreme form: word deafness = cannot recognise words, even though ability to hear pure tones remains intact
  (3) damage in parietal lobe: difficulty discriminating between syllables

Question 26

dual-stream model of speech perception

Answer 26

• ventral (what) pathway:
• ->identifying sounds/recognising speech
• -> starting in temporal lobe
• dorsal (where) pathway:
• -> locating sounds/linking acoustic sidle to the movements used to produce speech
• -> starting in parietal lobe