language - complexity of speech perception Flashcards
lecture 2 objectives
Understand why speech perception should be difficult
◦ The continuous flow of speech
◦ Coarticulation
Be able to describe how some features of language might aid speech s segmentation (e.g., word frequency, syllable stress)
Be able to describe how the categorical perception of phonemes helps us to recognise phonemes
Be able to describe factors that influence categorical perception of phonemes (e.g., speech rate, “lexical bias”)
why should speech perception be difficult
-because you cant find breaks between words, its like a long stream of speech, between individual words in a sentence
-this isn’t a problem in your first language
what is the segmentation problem
-how do we segment speech up into its individual words to understand what has been said to us
-we feel like we hear pauses between words to mark boundaries but this is an illusion
oronyms
what do they show us
a string of words or phrase that sounds the same as another string of words or phrase (a passage of speech you can slice up in more than one way
prove the segmentation problem
eg four candles fork handles , sounds the same
show us that there arent gaps between words, if there were they wouldn’t be difficult to splice up
coarticulation - problem
the articulation of two or more speech sounds together, so that one influences the other.
-vocal apparatus is constantly preparing for the next phoneme
eg “b” phoneme in “bill” “ball” “able” rob they are all different
what are the adv and disadv of coarticulation
adv
-allows speech to be faster and more fluent
-gives listener clues as to upcoming phonemes (our brain uses coarticulation to predict what it will hear next
complication
-no definitive acoustical pattern from any phoneme
-speech perception system has to see past these differences to recognise phonemes
how can we segment speech
-evidence from the speech perception system
-when we co articulate and blend all the sounds in the words , we tend to do it more within words than between words
-so where we have a boundary between two words, phonemes blend together less
-speech perception system sensitive to this as if it hears more coarticulation between phonemes, it will assume that’s within a word not between words
50 most commonly used words accounts for more than……..
how does our perception system use this to make intelligent guesses
more than half the speech we hear (Miller 1951)
-uses this info to make intelligent guesses around what its just heard
how does our speech perception system use word frequency to guess what we hear
the more common words (most common words) are used- eg if you hear something that sounds like thing or have it probably has heard it- and it can be used to make predictions, eg four candles , four is more frequent than fork so you would guess four is being said instead of fork candles
what is a syllable
rhythmic unit of speech
what is syllable stress
give examples
A stressed syllable has a longer, louder, and higher sound than the other syllables in the word
syllable stress can be strong or weak
REcord noun (a vinyl) stress is on the first syllable
reCORD (verb) recording eg stress is on the last syllable
-content words and function words
-content words-(open class words) -one of a huge number of words that convey meaning in a sentence i.e nouns, verbs,adjectives,adverbs
-function words(closed class words)-one of a limited number of words that do the grammatical work of language eg determiners and prepositions -the,a,to,in,and, and because
content and function words are stressed differently
-how
-content words tend to start with a stressed syllable
-function words tend to be unstressed
if you hear a _____ syllable it is likely to be at the start of a ______ word
-if you hear a weak syllable it is likely to be either towards the end of a _____ word , or the start of a _____ word
-how does speech perception make use of this
-if you hear a strong syllable it is likely to be at the start of a content word
- if you hear a weak syllable it is likely to be either towards the end of a content word, or at the start of a function word
-makes use of this -its called the metrical segmentation startegy
evidence for syllable stress being used to segment speech
-cutler and butterfield (1992) looked to see whether we used syllable stress to segment speech
-they got people in a lab and played them sequences of words that violated this rule (presented items like conDUCT aSCENTS upHILL), -so has no meaningful context to aid segmentation and has a stress pattern that violates our expectations
-they found that these items reliably induced mishearing in their participants eg participants heard “the doctor sends the pill” “a duck descends some hill”
eg doctor (they heard duct (the stressed syllable) and thought this must be the start of the word (proving syllable stress))
-this wouldn’t happen unless their speech perception system was using information to guide them to segment up speech stream
