SPECIFIC LANGUAGE IMPAIRMENT (SLI)
المؤلف:
John Field
المصدر:
Psycholinguistics
الجزء والصفحة:
P276
2025-10-13
315
SPECIFIC LANGUAGE IMPAIRMENT (SLI)
A condition in which a child who appears otherwise normal fails to acquire language like its peers. These children sometimes have restricted vocabularies or make relatively basic errors of grammar. They may show problems of comprehension as well as problems of production: finding it difficult to follow the utterances of others or to put thoughts into words. In particular, they seem to have difficulty in sustaining a contextual framework for a conversation. What is striking is that this linguistic deficit cannot be clearly linked to low intelligence or cognitive impairment. It appears to affect language but not other faculties.
Some researchers believe that the condition provides convincing evidence that language is modular and distinct from other forms of cognition. Others take the view that the underlying causes are most likely cognitive or perceptual.
Early research into SLI sought a link with hearing difficulties caused by otitis media with effusion (OME), a disorder of the middle ear which causes some hearing loss. This view is no longer generally held, and more recent commentators have suggested that SLI may result from a deficit in the child’s ability to recognise recurring patterns such as inflections in the language it encounters.
Those who adopt a nativist view maintain that innate grammatical components within Universal Grammar are defective or absent in SLI sufferers. An important study of three generations of a family (Gopnik, 1990) suggested that about half of them suffered severely from SLI and thus that the condition might be genetic. These individuals performed quite well on general grammaticality judgement tasks but their language lacked many important inflectional markings such as number, gender and verb endings. The initial conclusion drawn (the ‘feature-blindness’ hypothesis) was that their representation of grammar lacked an important component which enables others to recognise and acquire inflectional morphology. However, it was later suggested that SLI sufferers adopt a strategy of learning exemplar by exemplar instead of recognising that inflectional marking can be derived by rule. This means that they have difficulty in using inflections because the process of retrieving them makes heavy demands on memory. A strong version of this hypothesis is, however, difficult to square with evidence that SLI sufferers sometimes over generalise inflectional endings (goed), showing that they have some awareness of the system.
A contrary view attributes the absence of inflections in the language of SLI sufferers to inadequate perception. It finds a cause in the low salience of grammatical morphemes, which (in English) are weakly stressed and short in duration. English-speaking children suffering from SLI have been compared with Italians whose language has more perceptible inflectional markings. The Italian children showed a more extensive use of inflection and a preference for the more salient feminine articles la and una rather than the masculine il and un.
However, there are some reservations about the perceptual account. First, SLI appears to affect written as well as spoken language (though it could be that children simply do not write inflections because they do not perceive them). Second, no correlation has been established between the perceptual prominence of a feature and the likelihood that it will be absent from the speech of an SLI sufferer. If anything, the appearance of a particular inflection or functor seems to be determined by its grammatical function: final-s is more likely to be used for a noun plural than to mark possession or Present Simple Third Person. Children with SLI also have difficulty with inflections and functors that are not phonologically weak, such as irregular past tense forms and direct object pronouns. Finally, there is the argument that, if a perceptual deficit affects the recognition of certain inflectional features, there should be an impact upon wider syntactic knowledge (for example, the recognition of word classes).
A third possibility is that SLI may not be a unitary disorder but the result of a combination of several different forms of language impairment which are present to different degrees in different sufferers. Clinically based accounts have suggested a number of subtypes representing the symptoms which appear to co-occur in cases of SLI and of autism.
See also: Autism, Disorder, Modularity1, Savant, Williams Syndrome
Further reading: Bishop (1997); Fletcher (1999); Gopnik et al. (1997)
الاكثر قراءة في Linguistics fields
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