Specific Language Impairment: A Review of Current Trends and Issues for Future Research

Abstract

The most prominent manifestation of specific language impairment (SLI) is the omission of grammatical morphemes, such as inflectional affixes and function words. The source of this grammatical deficit has not yet been determined, although various hypotheses have been proposed to account for it. The present paper examines 2 of these hypotheses, viz., those subsumed under the phonological processing deficit hypothesis, in order to assess their validity. More specifically, it examines whether it is possible for the problem of processing rapid sound change in temporal sequence, and the decreased capacity of phonological working memory/phonological short-term memory to provide an adequate explanation for the manifestations of grammatical deficit in individuals with specific language impairment. Future research should address the following: the appropriate selection of participants with specific language impairment when conducting a cross-sectional study, considering the existing subtypes that exhibit different linguistic manifestations, and, when conducting a longitudinal study, appropriate selection of participants with regard to age. Some language aspects that should be focused on from a linguistic point of view are also suggested, in order to determine characteristics of the grammatical deficit of Japanese individuals with specific language impairment. Finally, some technical issues are mentioned that should be addressed when designing language tests. (PsycINFO Database Record (c) 2016 APA, all rights reserved)