• UNIVERSITY OF ESSEX

• DEPARTMENT OF LANGUAGE AND LINGUISTICS

• GRADUATE  PROGRAMME IN LANGUAGE DISORDERS

• IOANNA PATIOU

• COLCHESTER 2003

    Specific language impairment (SLI), also known as developmental aphasia refers to the failure of some children to acquire spoken language at the expected rate. Although, these children seem to be developing normally, they have normal intelligence, normal hearing acuity and no evidence of behavioral or social problems.    SLI is a rare syndrome which is genetically transmitted. According to the American Psychiatric Association “1 child in every 1000-2000 children may fit this description”. (Lahey M, 1998, pp 49) Leonard estimated that males could capture it 3 times more easily than females.

   SLI children have problems in language production and comprehension. This contributes to learning and reading disabilities and difficulties in understanding. In grammar, they have problems with “articles, particles, possessive –s, auxiliaries, number, agreement, case and tense marking”. (Radford, 2003, pp 3) More specifically, they have a delay or a deficit in the use of function morphemes and grammatical morphology, such as past tense –ed.

Literature review

    SLI has occupied, and still does, a lot of scientists all over the world who are trying to give a clearer picture about this syndrome. The models which we will test are the following:      The Perceptual Deficit was developed by Leonard LB. He claims that SLI children have specific difficulties in perceiving and processing general rules in their grammar due to the inflectional morphemes, which have low phonetic substance. So the processing of non-salient phonological segments is responsible for their inability to construct morphological paradigms (a set of related morphemes), e.g. past tense –d, thus for the verb watched, they have to relate it with watch because they pertain at the same set and then add –ed for past. (Leonard, 1998) This process causes problems to SLI children because the formation for grammatical representations is incomplete. Leonard explains that the low phonetic substance morphemes are “ nonsyllabic consonants and unstressed syllables, which have shorter durations than adjacent morphemes”. (Leonard, 1998, pp 92) And adds that SLI children will have more difficulties in forming regular past tenses (by marking the low phonetic substance –d, with an unstressed vowel), than irregulars, (which needs just a phonetically substantial stressed diphthong). (Radford, 2003, pp 6) His theory reaches to the conclusion that “ SLI children don’t have any fundamental problem with their grammar, although they present reduced speed of processing”. (Leonard 1998, pp 249)     Myrna Gopnik, developed the Feature Blindness Hypothesis and supported that the language impaired children suffer from a serious and possibly permanent global deficit which affects their grammar as a result of a defective grammar gene. Thus, these children can’t acquire syntactico-semantic features (tense, number, person) and so they are absent from their speech. (Radford 2000, pp 10) More simply SLI children don’t mark tense in obligatory contexts and so they make omission errors, (e.g. instead of past tense form, they use bare/infinitive verb) and commission errors, (e.g. they may use past tense in contexts where they should use present tense). The general conclusion is that SLI children will use past tense alike, either in past or present contexts and that they will equally often fail to mark it on regular and irregular verbs.   Gopnik reached to these conclusions after a case study of an 8 year old Canadian SLI child. She found that although there are some adverbs like: yesterday, which require past tense forms, he used them with unmarked verbs.    Gopnik and Crago, formulated the Rule Deficit Hypothesis. They sustained that SLI children are unable to construct grammatical and syntactical rules with result, either to memorize inflected forms as separate lexical items or to use rules that they were taught, e.g. add – ed for past tense forms. (Radford 2000, pp 17) This explains why they don’t use frequently grammatical morphemes. So it’s expected that SLI children will perform better on irregular past tense forms than on regulars. (Gopnik M 1994, pp 131-132) But it should also be mentioned that the frequency effect plays important role in their ability to retrieve the memorized form. They refer that the more frequently an SLI child uses or hears a past tense form, the better is going to be in the production of this form in comparison with the past tense form of a verb which he/she doesn’t use or hear so frequently. Lastly, they report that SLI children don’t produce novel or “overregularized past tense forms in their speech”. (Radford, Atkinson, Britain, Clahsen, Spencer 1999, pp 251)