First Language Acquisition, Developmental Language Disorders and Executive Function

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First Language Acquisition, Developmental
Language Disorders and Executive Function

• Anne Baker (ACLC)
• Michiel van Lambalgen (ILLC)

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Content of the talk

• The language behaviour of children with Specific
  Language Impairment (SLI)
• Theoretical explanations
• Executive functions

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What is Specific Language Impairment (SLI)?

• SLI refers to pervasive impairment in the
  development of language (in the absence of other
  problems)
• Deficits may be apparent in all domains of
  language, but some domains appear to be more
  affected than others.

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Affected Domains

• Grammar Verb morphology is particularly
  affected, but this varies between languages.
• (project on inflection and SLI)
• Explanations
• SLI is a representational deficit
• Agreement Deficit hypothesis (Clahsen)
• SLI is a processing deficit
• Sparse morphology hypothesis (Leonard)
• Evidence that this is the most promising
  explanation but possibly not for all children?

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Affected Domains

• Phonology some have clear phonological problems
  in their speech, but most seem to do badly on
  non-word repetition task
• (project on non-word repetition in SLI)
• Explanation central phonological processing
  deficit
• BUT recent results (Rispens Parigger) indicate
  the non-word repetition is associated with
  reading problems not per se with SLI

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Affected Domains

• Reading In addition to spoken language problems,
  children with SLI often also show reading
  problems
• Approximately 50 of children with SLI are also
  diagnosed with developmental dyslexia (McArthur
  et al. 2000)
• Explanation central phonological processing
  deficit

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Alternative explanations

• Is there a link with non-linguistic Executive
  Function?
• Could there be a totally different explanation of
  SLI that will cover all or some of these children?

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Back to tense

• Deficits in tense marking prominent in SLI - is
  this morphosyntactic problem only? (Clahsen)
• This depends on the grammar formalism adopted
• E.g. in unification-based grammars tense
  violations are semantic
• Yesterday, Vincent paints his boat
• Morphosyntactically fine!

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Tense and discourse

• Tense also has important discourse functions -
  facilitating computation of event structure
• Deficits in tense production may point as well to
  difficulties with corresponding discourse
  operations
• For which there is evidence in ADHD (vL, van
  Kruistum Parigger)
• Here is a link between tense and executive
  function

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What is executive function?

• An umbrella term for processes responsible for
  higher-level action monitoring and control
• that are necessary for maintaining a goal
• and achieving it in possibly adverse circumstances

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Executive function is composed of

• Planning (i.e. devising a linear order of
  actions)
• Initiation (of action sequences)
• Inhibition (...)
• Monitoring (...)
• Co-ordination (...)
• Control (...)
• Goal maintenance in working memory

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Computational aspects of EF

• Given the goal, compute the plan leading toward
  the goal using regression
• Uses world-knowledge (search) and unification, to
  apply general rule to particular situation
• Re-computation of the plan if new circumstances
  (monitoring) make the original plan no longer
  feasible
• This requires inhibition

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What has logic got to do with it?

• Logic provides a high-level formal description of
  executive function, as
• Closed world reasoning for rules allowing
  exceptions
• This gives theoretical coherence to the concept
  of EF
• And constructs a bridge from EF to language

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Why is EF relevant to language (disorders)?

• Connections between planning and language
• Syntax (Greenfield, Steedman, ...) same
  recursive structure as in planning?
• Discourse coherence (Slobin, Trabasso,..) are
  events described by sentences linked together
  like actions in a plan?
• Also semantics ...

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Why is EF relevant to language (disorders)?

• Semantics suppose the meaning of a sentence is
  given by a discourse model (Kamp, ...)
• Claim the computation of the discourse model is
  the brief of EF
• The discourse is a set of goals
• The discourse model is a plan to achieve the goals

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Discourse models as plans tense

• Verb tenses are formally represented as goals in
  the same sense as goals are used in planning
• The goal is to introduce the event corresponding
  to the tensed VP into the event structure
• Goal has to components
• to locate of event in time
• to mesh it with events already present

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Putting 2 and 2 together

• Semantic computations (or at least some) are
  analogous to computing a plan
• EF is responsible for motor planning
• Hypothesis EF is also responsible for
  planning-like computations for language
• Therefore, disorders in EF should correspond to
  language disorders (and conversely)
• Applications to ADHD Go/NoGo tasks relate to
  verb tense