W11.2 (N): Speech perception and comprehension

Question 1

How and why is speech variable? (five reasons)

Answer 1

Each word takes on a different acoustic shape each time it is uttered, this is due to:
- speaker (vocal track size, regional accent etc), - articulation rate (4/5 syllables per second in sentences)
- prosody (rhythm, melody, amplitude)
- mode (voice, whispered, creeky etc)
- coarticulation: individual phonemes influenced by preceding/upcoming segments i.e. regressive and progressive assimilation

Question 2

How is speech quasi-continuous?

Answer 2

Speech has no unique/systematic way to flag word boundaries i.e. there is rarely silence between two words
Short silences typically correspond to vocal tract closing to produce so called plosive consonants

Question 3

How is speech lexically ambiguous?

Answer 3

Words are made out of a limited number of sounds and syllables, therefore, embedded words are everywhere, inside other words
Ambiguity also arises due to straddling words as soon as we put two words together

Question 4

How is speech audovisual?

Answer 4

Trade off between acoustics and vision- visual information given by the lips and adjacent areas of the face about articulation is integral to speech perception, when available

McGurk and McDonald’s 1976 fusions- from the moment the face is present, these cues are integral to what we interpret - what you see is ambiguous e.g. ‘ga’ and ‘da’- modulating what you hear by what you see

audtion + vision = perception

Question 5

What are the four questions about speech and spoken word recognition?

Answer 5

1. Speech is variable
2. Speech isquasi-continuous
3. Speech is lexically ambiguous
4. Speech is audo visual

Question 6

How did Werker study how we acquire the phonemic categories of the native language?

Answer 6

Wanted to investigate how newborns could learn the sound of their native language and discriminate non native contrasts during the first year of life
Cross language speech perception- evidence for perceptual reorganisation during the first year of life
Found that newborns seem to come equipped to deal with phonetic contrasts
With exposure to the language, non native contrasts disappear but native contrasts are maintained
Study shows at 6 or 9 months old, the babies turn their head but at 12 months of age, babies no longer perceive the distinction between native and non native sounds
Shows newborns are born with much better skills than adults for distinguishing language
As newborns commit to their native language, their non native contrast that is not useful to them tends to disappear and we focus on only what is useful
Newborns are better at receiving phonetic contrast