Proposed Hypothesis in the Field of Specific Language Impairment

Since characteristics of specific language impairment (SLI) are not well known yet, and several hypotheses have been proposed in different investigations, periods and languages, it seems necessary to investigate it in different languages. There are some hypotheses about dependency of impairment to language characteristics and these hypotheses are other reason for necessity of examining the SLI in different languages. To investigate SLI, the first step is to identify and understand the various assumptions in the field. Therefore, the aim of the study was to explain different hypothesis about SLI.
For this purpose, special articles related to SLI was gathered by using Science Direct, Elsevier and Google Scholar, data bases, between 1970-2014 and 58 article reviewed.
Studding different hypotheses indicate that development in linguistic theories, result in changes in hypotheses and develop new hypothesis. Additionally, it has been shown that we can classify and study hypotheses with different view points, or choose and study one of them that is language-specific.