Developmental language disorder (DLD) is identified when a child has problems with language development that continue into school age and beyond. The language problems have a significant impact on everyday social interactions or educational progress, and occur in the absence of autism spectrum disorder, intellectual disability or a known biomedical condition. The most obvious problems are difficulties in using words and sentences to express meanings, but for many children, understanding of language (receptive language) is also a challenge. This may not be evident unless the child is given a formal assessment. Classification Terminology The term developmental language disorder (DLD) was endorsed in a consensus study involving a panel of experts (CATALISE Consortium) in 2017. The study was conducted in response to concerns that a wide range of terminology was used in this area, with the consequence that there was poor communication, lack of public recognition, and in some cases children were denied access to services. Developmental language disorder is a subset of language disorder, which is itself a subset of the broader category of speech, language and communication needs (SLCN). The terminology for children's language disorders has been extremely wide-ranging and confusing, with many labels that have overlapping but not necessarily identical meanings. In part this confusion reflected uncertainty about the boundaries of DLD, and the existence of different subtypes. Historically, the terms "developmental dysphasia" or "developmental aphasia" were used to describe children with the clinical picture of DLD. These terms have, however, largely been abandoned, as they suggest parallels with adult-acquired aphasia. This is misleading, as DLD is not caused by brain damage. Although the term DLD has been used for many years, it has been less common than the term specific language impairment (SLI), which has been widely adopted, especially in North America. The definition of SLI overlaps with DLD, but was rejected by the CATALISE panel because it was seen as overly restrictive in implying that the child had relatively pure problems with language in the absence of any other impairments. Children with such selective problems are relatively rare, and there is no evidence that they respond differently to intervention, or have different causal factors, from other children with language problems. In the UK education system, the term speech, language and communication needs (SLCN) is widely used, but this is far broader than DLD, and includes children with speech, language and social communication difficulties arising from a