Mother tongue has say in specific language impairmentWEST LAFAYETTE, Ind. -- A cross-cultural study of more than 200 children with a disorder called "specific language impairment" shows that a child's native language may have a lot to say about the number and types of problems associated with the ailment.
"There is no question that all children with this disorder seem to have some extraordinary problems in the use of some grammatical details, but the number and the specific types of grammatical details will vary from language to language," says Purdue University Professor Laurence B. Leonard.
Specific language impairment is a disorder in which children with normal intelligence and hearing have difficulty in acquiring and using language. Though the disorder affects 5 percent to 7 percent of all children starting school, researchers have not been able to clearly identify the source of the problem.
Leonard presented his findings Saturday (1/23) at the American Association for the Advancement of Science annual meeting in Anaheim, Calif.
The findings provide new insights into the nature of the disorder, which prevents millions of children from keeping up in the classroom, and they also may suggest new ways to treat it.
Leonard, who is the Rachel E. Stark Distinguished Professor of Audiology and Speech Sciences at Purdue, has studied specific language disorder across languages since 1987. In his latest study, involving co-investigators in Italy, Israel, Sweden and the United States, he set out to see if the symptoms of the disorder are universal.
"We were especially interested in whether particularly conspicuous symptoms seen in English-speaking children with specific language disorder might also be evident in children with the disorder who were acquiring these other languages," he says. "If so, the shared symptoms might represent a common denominator -- a key to understanding the source of the problem."
In the study, 4- to 7-year-old children with specific language disorder were tested on a range of grammatical usage. The results were compared to those obtained from two groups of normally developing compatriots -- those of the same age and those who were two years younger.
In all languages, children with the disorder were slower in acquiring their first words, were later at producing sentences, and had difficulty with some of their speech sound skills, Leonard says. But the number and specific types of problems the children encountered varied with the language.
"In English, one of the hallmark characteristics of specific language disorder is an extraordinary difficulty in grammatical morphemes -- grammatical inflections such as the 'ed' verb ending in 'The horse jumped over the fence' and function words such as 'is' in 'The horse is running,'" Leonard says. "Even though preschoolers with specific language disorder may be one or two years behind their peers in a wide range of vocabulary, speech sounds and grammatical skills, their use of these kinds of grammatical morphemes can be three or more years behind."
The study showed that such grammatical morphemes were not nearly as difficult for children learning languages such as Italian, Hebrew and Spanish, where the language often provides a distinct ending or sound for each new tense, and verbs are inflected for tense and grammatical agreement.
"In these languages, children with specific language disorder differed from younger peers on a smaller proportion of tense and agreement forms than was true for English-speaking children," Leonard says, noting that in all languages, "creative use" errors reflecting grammatical rules -- such as "throwed" in place of "threw" -- were easy to identify.
"The fact that these children show evidence of creative use, even in the most problematic languages, indicates that they grasp important grammatical principles," he says. "This suggests that the greatest problem for these children resides in their limited ability to register and process subtle grammatical elements in adult speech, and not in their ability to understand grammatical principles."
The findings also show that if the language "packages" grammatical information in a certain way, children with specific language disorder may be more capable of acquiring the necessary language skills.
"There may be simple ways of manipulating the input so that the grammatical details that are notoriously hard for kids in English will appear more frequently and conspicuously in our speech," he says.
"For example, in English, if we say 'Chris is jumping up and down,' the word 'is' is heard in a very brief form. In working with a child with specific language disorder, we might say something like, 'Is Chris jumping? Yes, I think he is. Chris is jumping up and down.' This puts 'is' at the end of a sentence, where it happens to be longer and more noticeable."
Leonard's study was supported in part by the National Institutes of Health's National Institute on Deafness and Other Communication Disorders.
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