Bilingual children acquire two languages, often using one language at home and another at school. Some bilinguals acquire both languages simultaneously from birth (simultaneous bilinguals), whereas others acquire one language at home and the second when schooling begins, around the age of 3 years or even later (sequential bilinguals). Specific language impairment (SLI) is a neurodevelopmental disorder with a genetic component affecting 7% to 10% of the population; the percentage is identical among bilinguals. This entry describes the language profile of children with bilingual specific language impairment (BiSLI) as well as assessment and treatment of these children.

As Gisela Håkansson and Ulrika Nettelbladt proposed in 1993 in one of the first studies of bilingual specific language impairment (BiSLI), a child should be diagnosed with BiSLI only ...