Dr. Sharon Armon-Lotem

SLI - Possible accounts

Specific Language Impairments in Children - Possible accounts

Background Reading on SLI

Leonard, L. B. (1997) Children with Specific Language Impairment. The MIT Press:

Definition

A developmental language disorder characterized by Gleason (2001, p. 504) as involving ‘delayed or deviant language development in a child who exhibits no cognitive, neurological or social impairment’. Children with SLI show impaired language development from birth (with problems which may either disappear during childhood or persist into adulthood) but are normal in other aspects of their physical, mental and social development (Radford 2006).

Exclusionary criteria (Stark & Tallal 1981) the child has no:

  • Hearing disabilities
  • Emotional or behavior problems
  • Performance IQ is –1.00 standard deviation or below
  • Observed neurological deficit
  • Severe articulation/phonological deficit

Frequency of SLI

Genetic basis of SLI

Neurological basis of SLI

Overall characteristics of SLI

Expressive vs. receptive deficit

SLI children typically show some (or all) of the following types of impairment:

  • Phonological (e.g. problems with consonant clusters and syllable-final consonants)
  • Grammatical (e.g. problems with affixes/inflections and articles/particles)
  • Lexical (delayed acquisition of words – e.g. first word appears around 23 months in SLI children, but around 11 months in TD children; SLI children also have word-finding problems)
  • Semantic (problems in determining the linguistic meaning of words, phrases and sentences, and understanding the meaning of metaphors)
  • Pragmatic (e.g. problems in the use of language in appropriate contexts)
  • Reading problems

Domain General Accounts (Not language specific)

  • Auditory (temporal processing) deficit hypothesis

Merzenich, M. Jenkins, W., Johnston, P., S., Schreiner, C., Miller, S. L. & Tallal, P., (1996) Temporal Processing Deficits of Language-Learning Impaired Children Ameliorated by Training, Science, v. 271, p. 77-81. (=Fast ForWord)

Task: discriminate between speech stimuli -six syllable contrasts ([ba] versus [da], [da] versus [ta], [ε] versus [ae], [dab] versus [daeb], [sa] versus [sta] and [sa] versus [sha]).

Findings:

  • LI group made most errors discriminating syllables which were differentiated by consonants and fewest errors on those differentiated by vowels.
  • The LI group was significantly poorer than the normal in discriminating all syllables that incorporated brief temporal cues followed rapidly in succession by other acoustic cues.
  • They also were impaired in discriminating [sa] versus [sha].
  • They were unimpaired discriminating stimuli differentiated by vowels.
  • Perceptual Deficit Model
Leonard, L. B.1989. Language learnability and specific language impairment in children.Applied Psycholinguistics10: 179-202

Following the sonority scale (Srlkirk 1984), Leonard proposes that SLI is an Auditory Perceptual Deficit:

  • Vowels and diphthongs are easier to perceive than consonants (and consonants are particularlydifficult to perceive when occurring in clusters of two or more successive consonants)
  • Stressed vowels are easier to perceive than unstressed vowels, long vowels and diphthongs are easier than short vowels, and full vowels are easier than reduced vowels
  • Procedural deficit hypothesis (PDH)

Ullman, M.T. & Pierpont, E.I. 2005. Specific Language Impairment is not Specific to Language: The Procedural Deficit Hypothesis. Cortex 41, 399-433.

Procedural memory: “mental grammar”, syntax, some morphology

Declarative memory: “mental lexicon”, vocabulary, idioms, irregular past-tense forms

"SLI can be largely explained by the abnormal development ofbrain structures that constitute the procedural memory system.”

  • a network of interconnectedstructures rooted in frontal/basal-ganglia circuits, subserves the learning and execution of motor and cognitiveskills.
  • recent evidence implicates that this system is important for specific aspects of grammar
  • a significant proportion of individuals with SLI suffer from abnormalities of this brain network, leading to impairments ofthe linguistic and non-linguistic functions that depend on it
  • grammatical and lexical retrieval deficits are strongly linked to dysfunctions of the basal ganglia (BG), and of the frontal cortex, esp. Broca’s area

Domain (Language (Grammar)) Specific Accounts

  • Feature Deficit Model

Gopnik, M. 1990. Feature blindness: A case study. Language Acquisition 1: 139-164

Due to a genetic deficit SLI children do not have grammatical (syntactic-semantic) features in their grammar. This is a global deficit.

  • Rule Deficit Model

Gopnik M & CragoMB.1991. Familial aggregation of a developmental disorder.Cognition 39: 1-50

Studying three generations of a family in London, Gopnik & Cargo concluded that they have the same syntactic abilities as MLU matched controls, but could not generate morphological rules (due to genetic failure of the dual mechanism of morphological acquisition).

  • Agreement Deficit Model

Clahsen H, Bartke S and Göllner S. 1997. Formal features in impaired grammars: a comparison of English and German SLI children.Journal of Neurolinguistics 10: 151-171

Findings: Past tense - 76% of main verbs and 89% of auxiliaries

3Sg present tense - 49% of main verbs and 35% of auxiliaries

SLI children have problems with acquiring uninterpretable features, which make no contribution to the meaning of the sentence (semantically redundant), e.g., agreement features.

Tsimpli and Stavrakaki (1999) and Tsimpli (2001) - Uninterpretable Feature Deficit Model

  • Agreement-and-Tense-Omission Model (Extended Optional Infinitives)

Wexler K, Schütze C & Rice M (1998) ‘Subject case in children with SLI and unaffected controls:Evidence for the Agr/Tns Omission Model’, Language Acquisition 7: 317-344

TD children omit either TNS or AGR or neither up to the age of 3. In SLI children this is extended until the age of 7-8.

Is SLI only about tense and agreement?Is it only about the functional system?

  • Dependency Deficit Model

Van der Lely HKJ and Battell J (2003) ‘Wh-movement in children with grammatical SLI: A test of theRDDR hypothesis’, Language 79: 153-181

"SLI children have problems in handling non-local dependencies (between pairs of constituents which are not immediately adjacent) such as those involved in tense marking (which involves a T-V dependency both in the agreement-based analysis of Adger 2003 and in the Affix Hopping analysis of Radford 2004), agreement (which involves a subject-verb dependency), determining pronominal reference (which involves a pronoun-antecedent dependency), and movement (which involves a dependency between two constituents, one of which attracts the other)."

  • Deficit in Computational Grammatical Complexity (CGC)

Marinis, T. & van der Lely, H. K. J. (2007). On-line processing of wh-questions in children with G-SLI and typically developing children. International Journal of Language & Communication Disorders 42(5), 557-582.

“The CGCHypothesis claims that the core deficit in some but not all forms of SLI is in therepresentation and/or mechanisms underlying the construction of hierarchicalgrammatical structures.1 For G-SLI children their grammar is characterized byGrammatical Structural Economy in syntax, morphology and for most phonologytoo. Thus, the least complex structure will surface. Within the syntactic component,the core deficit is in computing syntactic dependencies between constituents. WithinChomsky’s Minimalist Program (Chomsky 1995), this can be implemented asoptionality of the operation Move, which is not ‘automatic’ and ‘compulsory’.Further, complexity is defined as the number of movement operations, thus subjectquestions are predicted to be less problematic than object questions because theformer has one less movement operation (van der Lely and Battell 2003). van derLely and colleagues demonstrated that the CGC hypothesis accounts for a widerange of phenomena in English G-SLI children.”.

Long distance syntactic relations - Passive

Maryi was kissed ti by John

  • Passive is A-movement rather than A’-movement
  • The subject is the patient (no necessary agent)
  • The transitive verb has unique morphology (with or without an auxiliary verb) which makes it intransitive
  • The passive derives n-place predicate from n+1-place predicate
  • Not all languages permit an agent-phrase (by phrase), and the same agent-phase can occur with non-passive verbs
  • Verbal vs. adjectival passive (unaccusative vs. passive)

The girl is covered (by the boy)

The covered girl (*by the boy)

Ha-yalda mexusa (al yedey ha-yeled)

the-girl cover-pass (on hands the-boy)

‘The girl is covered (by the boy)’

Issues in acquisition:

  • Reversible vs. non-reversible
  • Actional vs. non-actional
  • Adjectival vs. verbal
  • Do children understand the by-phrase?
  • Comprehension vs. production

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