ABSTRACT
By definition, individuals with language impairments have reduced ability in language-any language and all languages. Many language impairments are explained by obvious damage to sensory, cognitive or neurological systems, as is the case in hearing loss, mental retardation or dementia. For individuals with primary language impairments the most obvious area of difficulty is with language. Developmental and acquired primary language impairments are high-incidence disabilities among single-language speakers and most likely affect bilingual populations in similar numbers. For example, a subset of children learning one language from birth and a second language beginning in early childhood lag behind their sequential bilingual peers in communication skills for no readily apparent reason. This weakness in language persists through adolescence and into adulthood. In other cases, adults who once spoke two languages proficiently have chronic difficulty communicating in either language following a stroke, although other major systems seem well preserved.
