Historically, several different diagnostic terms have been used to describe developmental language learning deficits of unknown origin in children. These include developmental aphasia , congenital aphasia , developmental dysphasia , and specific language impairment (SLI). More recently, the term language learning impairment (LLI) has been used. This shift in terminology is based on research findings that demonstrate that the deficits these children have are rarely specifically linguistic, as well as on findings derived from longitudinal studies that demonstrate considerable overlap between oral language deficits and subsequent learning disabilities, including dyslexia.
Even a cursory look at both clinical and research criteria typically used for diagnosing LLI demonstrates that this is a diagnosis made primarily by exclusion. That is, LLI is diagnosed on the basis of standardized clinical test results that demonstrate a discrepancy between a child's chronological age and language age and a ruling out of developmental factors that could be responsible for the child's language problems. Although children with LLI all have significant deficits in processing nonlinguistic as well as linguistic auditory information, phonologic difficulties, and syntactic problems, the specific characteristics of this clinical syndrome vary from one child to the next.