We have a unique opportunity to conduct a large-scale genetics-first cognitive evaluation of children with 16p11.2 deletions and duplications. The focus will be on speech production, an area where we – and others – have previously observed deficits in the deletion cases (e.g., Fedorenko, Morgan et al., submitted). The study will include an extensive battery of standardized speech tasks, as well as additional language and cognitive assessments to help interpret the nature and specificity of the speech production deficits. Building on our prior work, this project will a) help address some limitations of our and others’ past studies (see details below), b) delve deeper into the nature of the speech production deficits in 16p11.2 deletion cases, and c) provide a detailed characterization of 16p11.2 duplication cases, i) whose cognitive abilities are quite poorly characterized to date, and ii) who provide an important comparison group for the 16p11.2 deletion cases.