SummaryA small study was set up to investigate the prevalence of delayed language development in an urban sample of 3 year old children. Verbal comprehension, expressive language, articulation and intelligibility were assessed. Children from immigrant families performed particularly poorly on the assessment scales, and were not included in the subsequent analysis. In the remaining sample of 160 children, no child was found to have a severe developmental language disorder, and only one with a significant specific language delay which was still present at the age of 4 years. The sample was too small for a study of the prevalence of severe developmental language disorder, but some interesting suggestions emerged in relation to the effects of social grade, size of family and attendance at nursery school. Good language performance seemed to be related to a complex of high social grade, small family, and attendance at nursery school.