Language II
October 30, 2008
Speech/Language Production I
• Common Features of Models
– extensive pre-planning
– distinct stages of processing
– general (intended meaning)-to-specific
(utterance) organization
– most models use of speech errors as data
Spreading Activation Theory (Dell)
• four levels of activity
– Semantic (meaning)
– Syntactic (grammatical structure of words in the
planned sentence)
– Morphological (basic units of meaning or word
forms)
– Phonological (sounds)
• representation formed at each level
• processing occurs simultaneously at all levels
• uses speech errors as primary data
Spreading Activation (cont’d)
• Lexicon: connectionist network containing
nodes for concepts, words, morphemes, and
phonemes
• Insertion rules (which is highest activated?)
determine items selected for insertion into
sentences
• Errors predicted by model:
– Errors more likely when speaker has not formed a coherent
speech plan
– Errors should be from same category
– Anticipation errors (because of multiple activations; “The sky
is in the sky”)
– Exchange errors (because once selected, items’ activation
turns to zero (“I hit the bat with my ball”)
Speech Production II
• Levelt/Bock approach
– four stages: message, functional
processing, positional processing, and
phonological encoding
– information about syntax (lemma) available
before sound (lexeme)
– consistent with TOT phenomenon
Bock & Levelt (1984)
Intended
meaning
Selection of
word concepts,
grammatical
construction
Ordering parts
of sentence,
adding
inflection
Phonological
and prosodic
elements
worked out
ERRORS
Semantic substitution
(“tennis bat”), blending
(“sky is shining”), wordexchange errors (“let the
bag out of the cat”)
Morpheme exchange errors
(“trunked two packs”),
spoonerisms (“hissed my
mystery lectures”) within
same clause
WEAVER++ (Word-Form
Encoding by Activation
and Verification)
Neuropsychological evidence of
staged selection
• Content-word retrieval vs. syntactic
processing
• Distinction between anomia (e.g., word
selection difficulties) vs. agrammatism
(inability to construct grammatically correct
sentences)
• Jargon aphasia: can construct grammatically
correct sentences but not find correct words
Processes in Writing (Hayes &
Flower, 1980)
• Planning: generating info from LTM,
organizing
• Translating: producing language
conforming in meaning to that retrieved
in the planning stage
• Reviewing: editing what is written
Deep
Dysgraphia
Phonological
Dysgraphia
Language Disorders
Types of Disorders
• Aphasia: acquired disorder of language due
to brain damage
• Dysarthria: disorder of motor apparatus of
speech
• Developmental language disturbances
• Associated disorders
– Alexia
– Apraxia
– Agraphia
Major Historical Landmarks
• Broca (1861): Leborgne: loss of speech
fluency with good comprehension
• Wernicke (1874): Patient with fluent
speech but poor comprehension
• Lichtheim (1885): classic description of
aphasic syndromes
C
A
M
Lichtheim’s Model
Arcuate fasciculus
Contemporary anologues of Lichtheim’s (1885) Aphasic Syndromes
Syndrome
Symptom
Deficit
Lesion
Broca’s Aphasia
 speech production;
sparse, halting speech,
missing function words,
bound morphemes
Impaired speech planning
and production
Posterior aspects of 3rd
frontal convolution
Wernicke’s
Aphasia
 Auditory
comprehension, fluent
speech, paraphasia, poor
repetion and naming
Impaired representation of
sound structure of words
Posterior half of the first
temporal gyrus
Pure motor
speech disorder
Disturbance of
articulation, apraxia of
speech, dysarthria,
aphemia
Disturbance of articulation
Outflow from motor cortex
Pure Word
Deafness
Disturbance of spoken
word comprehension,
repetition also impaired
Failure to access spoken
words
Input tracks from auditory
cortex to Wernicke’s area
Transcortical
Motor Aphasia
Disturbed spontaneous
speech similar to BA;
relatively preserved
repetition, comprehension
Disconnection between
conceptual word/sentence
representations and motor
speech production
Deep white matter tracks
connecting BA to parietal
lobe
Transcortical
Sensory Aphasia
Disturbance in single word
comprehension with
relatively intact repetition
Disturbed activation of
word meanings despite
normal recognition of
auditorily presented words
White matter tracks
connecting parietal and
temporal lobe
Conduction
Aphasia
Disturbance of repetition
and spontaneous speech,
phonemic paraphasia
Disconnetion between
sound patterns and
speech production
mechanisms
Arcuate fasciculus;
connection between BA
and WA
Additional Aphasia Syndromes
Syndrome
Symptom
Deficit
Lesion
Anomic Aphasia
 single-word
production, marked for
common nouns;
repetition and
comprehension intact
Impaired storage or
access to lexical entries
Inferior parietal lobe or
connections within
perisylvian language
areas
Global Aphasia
 Performance in all
language functions
Disruption of all/most
language components
Multiple perisylvian
language components
Isolation of the
language zone
 Spontaneous speech,
comprehension, some
preservation of
repetition; echolalia
common
Disconnection between
concepts and both
representations of word
sounds and speech
production
Cortex outside
perisylvian association
cortex
Broca’s Aphasia
•
•
•
•
•
Telegraphic, effortful speech
Agrammatism
Some degree of comprehension deficit
Writing and reading deficits
Repetition abnormal – drops function
words
• Buccofacial apraxia, right hemiparesis
M.E.
Examiner.
M.E.
Examiner.
M.E.
Examiner.
M.E.
Examiner.
M.E.
Cinderella ... poor ... um 'dopted her ... scrubbed floor,
um, tidy ... poor, um ... 'dopted ... Si-sisters and mother ...
ball. Ball, prince um, shoe ...
Keep going.
Scrubbed and uh washed and un...tidy, uh, sisters and
mother, prince, no, prince, yes. Cinderella hooked prince.
(Laughs.) Um, um, shoes, um, twelve o'clock ball,
finished.
So what happened in the end?
Married.
How does he find her?
Um, Prince, um, happen to, um ... Prince, and Cinderalla
meet, um met um met.
What happened at the ball? They didn't get married at the
ball.
No, um, no ... I don't know. Shoe, um found shoe ...
Wernicke’s Aphasia
•
•
•
•
•
•
Fluent, nonsensical speech
Impaired comprehension
Grammar better preserved than in BA
Reading impairment often present
May be aware or unaware of deficit
Finger agnosia, acalculia, alexia without
agraphia
Wernicke description of “Cookie Theft Picture”
C.B.
Uh, well this is the ... the /dødøü/ of this. This and this and this and
this. These things going in there like that. This is /sen/ things here. This one here, these
two things here. And the other one here, back in this one, this one /gø/ look at this one.
Examiner.
Yeah, what's happening there?
C.B.
I can't tell you what that is, but I know what it is, but I don't now where
it is. But I don't know what's under. I know it's you couldn't say it's ... I couldn't say what it
is. I couldn't say what that is. This shu-- that should be right in here. That's very bad in
there. Anyway, this one here, and that, and that's it. This is the getting in here and that's
the getting around here, and that, and that's it. This is getting in here and that's the getting
around here, this one and one with this one. And this one, and that's it, isn't it? I don't
know what else you'd want.
Conduction Aphasia
•
•
•
•
•
Fluent language
Naming and repetition impaired
May be able to correct speech off-line
Hesitations and word-finding pauses
May have good reading skills
Global Aphasia
• Deficits in repetition, naming, fluency
and comprehension
• Gradations of severity exist
• May communicate prosodically
• Involve (typically) large lesions
• Outcome poorest; anomic
Transcortical Aphasias
Transcortical Motor
• Good repetition
• Impairment in
producing
spontaneous speech
• Good
comprehension
• Poor naming
•
•
•
•
•
Transcortical
Sensory
Good repetition
Fluent speech
Impaired
comprehension
Poor naming
Semantic
associations poor
Associated Deficits
• Alexia without Agraphia
– Impairment in reading with spared writing
• Apraxia
– Loss of skilled movement not due to
weakness or paralysis
Fundamental Lessons
• Language processors are localized
• Different language symptoms can be
due to an underlying deficit in a single
language processor
• Language processors are regionally
associated with different parts of the
brain in proximity to sensory or motor
functions
What Language Disorders Reveal
about Underlying Processes
• Pure Word Deafness: selective processing of
speech sounds implies a specific speechrelevant phonological processor
• Transcortical Sensory Aphasia: repetition is
spared relative to comprehension; selective
loss of word meaning; some cases suggest
disproportionate loss of one or more
categories
What Language Disorders Reveal
about Underlying Processes
• Aphasic errors in word production: reveal complex nature of
lexical access
– Phonological vs. semantic errors: independent vs.
interactive relationship?
– Grammatical class: nouns vs. verbs (category specificity)
• Broca’s aphasia: syntax comprehension and production
– Central syntactic deficit; loss of grammatic knowledge
– Problems in “closed-class” vocabulary (preposition, tense
markers)
– Limited capacity account
– Mapping account (inability to map from parsing to thematic
roles)
• Jargon Aphasia: can construct gramatically “better” sentences
than agrammatics, but can’t find words, producing neologisms;
reinforces distinction between content and grammatical struture
Prosody
• Linguistic vs. nonlinguistic prosody
• Evidence for hemispheric differences
• Clinical syndromes
– Disturbances of comprehension
• Auditory affective agnosia
• Phonagnosia
– Disturbances of prosodic output
• Aprosodias
Spontaneous Prosody
Good
Poor
Ross & Monnot (2007) Brain and Language
Ross & Monnot (2007) Brain and Language
Aphasia and the Semantic
System
• Meaning stored separately from form
• Models of representation in semantics
– Feature-based models (see categorization)
– Nondecompositional meaning
• Modality-specific semantic deficits:
optic aphasia as an example
Two Example Models of Semantic Organization
One Semantic System
Multiple Semantic Systems