Many children with specific language impairment (SLI) show serious limitations in grammatical ability. These limitations are often longstanding, and they represent one of the most reliable indicators of this disorder. An especially common manifestation of this grammatical weakness is the inconsistent use of grammatical morphemes that mark tense and agreement (e.g., -s in jumps and is in The girl is eating). Although the details of this inconsistent use have been well described in the scientific literature, an explanation for the protracted period of inconsistency has not yet emerged. The goal of this project is to test a new proposal regarding the possible source of the inconsistent use of tense and agreement morphemes by children with SLI. Experiments 1-5 are designed to test the hypothesis that children with SLI have difficulty interpreting sentences that contain subject-verb sequences lacking tense and agreement morphology (as in the girl go in the question Did the girl go? or the boy running in the sentence I see the boy running). As a result, they treat these sequences (e.g., The girl go) as grammatical and use them in their own speech. [Furthermore, because the sentence interpretation problems are still present when the children begin to form abstract rules for sentence use, generalizations from these improperly extracted sequences become the source for generating new utterances, thus prolonging the period of inconsistent use of tense and agreement markers.] The first five experiments are designed: (a) to identify the specific types of sequences that might be problematic (e.g., questions and/or complex sentences);and (b) to determine whether the children generalize misinterpreted sequences to form new (ungrammatical) utterances of the same type (e.g., does misinterpretation of the girl go in Did the girl go? lead to spontaneous generation of productions such as The cat go?). [In addition, these experiments include complex sentence comprehension and working memory tasks as predictors to determine the relative contributions that syntactic comprehension difficulty and working memory limitations make to the children's tendency to omit tense and agreement morphology.] Experiment 6 is an intervention study designed to determine whether the period of inconsistency with tense and agreement morphology can be significantly reduced by manipulating the language input the children receive. Specifically, it is predicted that inconsistency can be reduced by exposing the children to many sentences containing the target morphemes (e.g., The girl jumps, The boy is walking) and minimizing exposures of questions (e.g., Did the girl go?) and complex sentences (e.g., I see the boy running) that contain subject-verb sequences with no tense and agreement morphology. [Along with its clinical value, this experiment serves as a critical test of the causal role of input distribution on the children's sentence use.] The findings of this project should contribute to a greater understanding of the sources of grammatical limitations in children with SLI and provide important information concerning how best to treat the pervasive tense and agreement weaknesses seen in this disorder.

Public Health Relevance

Children with specific language impairment have a longstanding deficit in language ability that affects their social adjustment and academic achievement. The goal of this project is to discover the source of one of the most pervasive language difficulties of these children, a protracted period of grammatical inconsistency. The findings should lead to a greater understanding of this disorder and provide important information concerning methods of treatment.

National Institute of Health (NIH)
National Institute on Deafness and Other Communication Disorders (NIDCD)
Research Project (R01)
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Language and Communication Study Section (LCOM)
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Cooper, Judith
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Purdue University
Other Health Professions
Schools of Arts and Sciences
West Lafayette
United States
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Fey, Marc E; Leonard, Laurence B; Bredin-Oja, Shelley L et al. (2017) A Clinical Evaluation of the Competing Sources of Input Hypothesis. J Speech Lang Hear Res 60:104-120
Leonard, Laurence B; Deevy, Patricia (2017) The Changing View of Input in the Treatment of Children With Grammatical Deficits. Am J Speech Lang Pathol 26:1030-1041
Souto, Sofía M; Leonard, Laurence B; Deevy, Patricia et al. (2016) Subordinate clause comprehension and tense/agreement inconsistency in children with specific language impairment. J Commun Disord 62:45-53
Leonard, Laurence B; Fey, Marc E; Deevy, Patricia et al. (2015) Input sources of third person singular -s inconsistency in children with and without specific language impairment. J Child Lang 42:786-820
Pettenati, P; Benassi, E; Deevy, P et al. (2015) Extra-linguistic influences on sentence comprehension in Italian-speaking children with and without specific language impairment. Int J Lang Commun Disord 50:312-21
Purdy, J D; Leonard, Laurence B; Weber-Fox, Christine et al. (2014) Decreased sensitivity to long-distance dependencies in children with a history of specific language impairment: electrophysiological evidence. J Speech Lang Hear Res 57:1040-59
Agus, Trevor R; Carrión-Castillo, Amaia; Pressnitzer, Daniel et al. (2014) Perceptual learning of acoustic noise by individuals with dyslexia. J Speech Lang Hear Res 57:1069-77
Souto, Sofía M; Leonard, Laurence B; Deevy, Patricia (2014) Identifying risk for specific language impairment with narrow and global measures of grammar. Clin Linguist Phon 28:741-56
Leonard, Laurence B; Deevy, Patricia; Fey, Marc E et al. (2013) Sentence comprehension in specific language impairment: a task designed to distinguish between cognitive capacity and syntactic complexity. J Speech Lang Hear Res 56:577-89
Gladfelter, Allison; Leonard, Laurence B (2013) Alternative tense and agreement morpheme measures for assessing grammatical deficits during the preschool period. J Speech Lang Hear Res 56:542-52

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