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Flashcards

Speech Production

Eleni Blakemore Language, Communication and Thought (PS3022) English 43 cards

Cards in this deck (43)

  1. 1Ways to investigate speech production- Observations of movements of speech (MRI, electropalatography)
    - Recordings of acoustic product (coarticulation)
    - Analysis of natural and induced speech errors- spoonerisms
    - Neuroimaging studies-fMRI
    - Genetic investigations of speech
  2. 2How do we speak?Air flows from the lungs through the larynx where air passes over the vocal fold producing a noise
    Articulators shapes the noise: lips, tongue, jaw, soft palate
  3. 3What are formants?Frequencies that are enhanced
  4. 4PitchChange in the rate of vibrations
  5. 5Fitch (2010)Source-filter model
    Analogy of a lamp shining in a house
    Lamp (source) provides energy, windows (filters) determine how much light can escape, peaks in the light cast outside the house = formants
  6. 6PlosivesStop consonants
    Involve full closure of vocal tract
    P B K G T D
  7. 7Place of articulationPosition of vocal tract closure
    Labial (lips) = B P
    Alveolar (behind lips) = D T
    Velar (back of mouth) = G K
  8. 8VoicingCompressed air forces open closed vocal folds in the larynx
    Positive = B D G
  9. 9MannerHow a sound is articulated
  10. 10StopsComplete vocal tract closure followed by a burst release 'gave'
  11. 11FricativesTurbulent airstream through oral constriction
    Noisy sounds with lots of different frequencies
    S F T
  12. 12NasalsVelum closes off oral cavity
    Sounds produced in nasal cavity
    'man'
  13. 13VowelsNo closure but where tongue is placed
    Front, central, back
    Closed, close-mid, open-mid, open
  14. 14What is electropalatography?Technique used to measure movements of the tongue
    Electrodes measure where the tongue is positioned
    Advantage: temporal sensitivity
    Disadvantage: not natural speech
  15. 15What do the KE family show?Some show a severe developmental deficit in speech and language
    Problem in complex orofacial movements for speech
  16. 16Watkins et al. (2002)Also show deficits in language comprehension and production BUT not IQ- similar to those unaffected
  17. 17Fisher et al. (1998)Dominant gene on chromosome 7 - FOXP2
    Codes for transcription factor
    Important for neural development of CNS, heart + lungs
  18. 18Watkins et al. (2002)Brain structure in KE family of those affected and unaffected
    Reduced grey ,matter density in affected
    L + R caudate nuclei, L inferior frontal cortex + left SMA
    Did not affect grey matter in inferior frontal and motor regions - important for speech
  19. 19Fisher & Scharff (2009)Humans, monkeys, mice, rats, birds, crocodiles, zebrafish
    Reduced FOXP2= speech and language deficits in humans, impaired vocal learning in birds, abnormal synaptic plasticity + motor skill learning deficits in mice
  20. 20What are the many stages of speaking?Activation of a lexical concept (semantic message)
    Selection of correct synaptic structure (grammatically correct)
    Activation of phonological and phonetic code
    Coordination of muscles for articulation
  21. 21Levelt et al. (1989)Simple model of speech production
    Stages discreet, sequential
    1. Conceptualisation: identifying intended message (abstract level)
    2. Formulation: concepts into message (2 stages)
    Lemma-syntactic but not phonological specification (tip tongue)
    Lexeme-phonological word form
    3. Articulation: taking word form + executing phonemes
  22. 22Schreibers et al. (1990)RTs for picture naming task with auditory distractors
    Word semantically related (GOAT) before slowed naming of sheep picture
    Phonological distractor presented with or later speeds up naming (SHEET)- phonological facilitation
    Semantic concepts happen first
  23. 23Fromkin (1973)Speech Errors
  24. 24Example of exchange errorLet's go to Yew Nork
  25. 25Example of preservationI like cats and cogs
  26. 26Example of additionLet's go to the plub
  27. 27Example of substitutionEat with your knife and fingers
  28. 28Example of deletionIt was intentional (unintentional)
  29. 29Speech errors at a semantic levelWord substitutions: blonde eyes
    - Belong to same category as intended
    - Mostly affects content words
    - Many not sound like intended at all
    - Wrong semantic unit activated?
  30. 30Speech errors at a phonological levelPhoneme substitution: I like dogs more than hats
    Spoonerisms: You've tasted two worms
    - May not be semantically related
    - Lexical advantage- more likely to be word than non-word
    - Occur when wrong phoneme unit is activated
  31. 31Speech errors at a mixed levelMixed errors: I have to feed the rat
    Blend errors: The chung of today
    - Sound and mean similar things to intended
  32. 32Dell et al. (1986)Cascaded processing model to explain mixed errors
    Connections are bidirectional, most active phonemes are output
    Semantic feature to word or lemma to phoneme nodes
  33. 33Example of cascaded processing model using 'CAT'- Activates semantic nodes (furry, animal, small)
    - Activates similar lemma nodes (dog, rat)
    - Component phonemes are activated (cat and rat have 2 phonemes similar)
    - Activated + feedback to word form level (including MAT)
    - Over time, feedback + feedforward connections strengthen CAT + RAT over CAT + MAT
    - Explains why real words than non words
  34. 34Levelt (1999)Alternative explanation to mixed errors
    Internal Error Monitor-a checking system that might let something slip through
  35. 35Garnham et al. (1991)Make speech errors rarely
    1 in 900 words
  36. 36Dronkers (1996)Overlap of lesions sites in those with apraxia of speech
    All had damage to superior tip of pre central gyrus of the insula (SPGI)
    Stroke patients with no apraxia had this region spared
  37. 37What other regions have been found to be affected?Inferior frontal gyrus
    Basal ganglia
    Supplementary motor cortex
  38. 38Indefrey & Levelt (2004)Meta-analysis of 82 studies
    Speed production using different techniques (PET, MRI)
    Create a map of the simple model stages
    - Lemma selection is complete between 150-330ms post picture onset
    - Duration range for form encoding from 217-530ms
  39. 39Indefrey & Levelt (2000)Main components of word production networks are largely left lateralised
    Originally only four 6 common areas for picture naming and word generation
  40. 40DIVA ModelsDirection In Velocities of Articulators
  41. 41Tourville & Guenther (2010)DIVA model is an adaptive neural network that describes the sensorimotor interactions involved in articulator control during speech production
    Speech sound as input generates a time sequence of articulator positions that command movements of the stimulated vocal tract that produce the desired sounds
    Assign components of model to regions of the brain
  42. 42Based on ERROR prevention/reduction- Feedforward loops from speech planning regions send information about intended utterance to the auditory and somatosensory target maps
    - Actual sensory experience is compared with the target experience to calculate error
    - Feedback to the motor centres aims to reduce this error
  43. 43Guenther et al. (2009)26 year olds 'locked in'
    Principle of model
    Electrodes placed in ventral premotor cortex to intended formants
    Goes through a synthesiser to produce speech (brain computer interface)

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Language, Communication and Thought (PS3022) Flashcards on Speech Production , created by Eleni Blakemore on 16/05/2017.
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Eleni Blakemore
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