The influence of inherited genes

     Most types of Specific Language Impairment (SLI) are caused by the failure of many genes to interact as intended. However, a recent study has identified a single gene responsible for a language disorder found in about half of the members of one family living in London. Though they are all normal in other ways, their speech disorder is so obvious that people outside the family can’t understand them. It appears to result from the disruption of a single gene on chromosome 7, in the same area as a gene that has been linked to autism.

     Many researchers believe that some class of SLI may not be specific to language at all. In their view, the disorder may sometimes result from a problem with working memory, a short-term memory system for storing information, manipulating it, and using it to solve a problem. Some SLI sufferers may have difficulty with their short-term memory for speech sounds. In other cases, the short-term memory problem may be more general. One experiment showed that some SLI children have difficulty remembering and repeating back any sequence of sounds that they hear, even if they are not speech sounds. A well-functioning working memory helps with performance on a variety of language and reading related skills, such as building a good vocabulary, learning a foreign language, and becoming a proficient reader.