|Title:||The Grammatical Morpheme Deficit in Children with Hearing Impairment, Children with Down's Syndrome and Children with Specific Language Impairment||Add Dissertation|
|Author:||Maria McGuckian||Update Dissertation|
|Email:||click here to access email|
|Institution:||University of Ulster, Faculty of Social Sciences|
|Linguistic Subfield(s):||Morphology; Psycholinguistics; Language Acquisition;|
|Abstract:||Grammatical morphemes have been reported to be problematic for children whose language learning problems appear to derive from very different origins, including specific language impairment (SLI) (e.g. Leonard, Eyer, Bedore & Grela, 1997), Down's syndrome (DS) (e.g. Chapman, 1995) and hearing impairment (HI) (e.g. Norbury, Bishop & Briscoe, 2001). This thesis was designed to establish whether the nature of the grammatical morpheme difficulty is similar or different across (English-speaking) groups of children who present with moderate-HI, DS and SLI. It was hypothesized that the grammatical morpheme deficit would be more similar than different across these distinct clinical groups and that any obvious differences between the groups would be largely quantitative in nature.
A wealth of production data, including elicited as well as spontaneous speech data, was collected and analysed so that across-group comparisons could be made for rates of production of a range of grammatical morphemes (11 different forms – tense and non-tense morphemes), for types and proportions of grammatical morpheme errors and for order of grammatical morpheme accuracy.
In addressing the key hypothesis of the research there was first consideration of the nature of the grammatical morpheme deficit for each of the three clinical groups under study when compared to mean length of utterance (MLU)-matched typically developing children. Following that, explicit comparisons were made between the different clinical groups for patterns and rates of grammatical morpheme use.
In the main, the findings supported the key hypothesis showing many similarities between the various clinical groups for grammatical morpheme use. However, some intriguing differences also emerged.
The findings showed that the children with HI were sensitive to frequency of elements in input; perhaps until they reach a necessary threshold for spoken language intake. In contrast, the children with DS and SLI did not show the same sensitivity to input frequency. Rather, those children seemed to have extracted generalisations from the input. The findings showed that children with DS and SLI can present with command of forms like irregular past tense appropriate for chronological or mental age, whilst at the same time present with a deficit with many grammatical morphemes, including past tense –ed and possessive –s.
Additionally –and specific to SLI– the findings support research suggesting that problems with grammatical morphemes are less obvious in many older children with that condition.
The thesis findings contribute to understanding of grammatical morpheme acquisition in HI, in DS and in SLI and to knowledge of the underlying nature of grammatical morpheme acquisition generally. The findings indicate that the underlying linguistic system is ultimately regulated by a dual mechanism and that linguistic abstractions may be more dependent on specific linguistic experiences than a classic generative account would predict. Additionally, the research provides direct evidence that data from elicitation procedures can be as representative a measure of children's use of grammatical morphemes as spontaneous speech data.