The main focus of the Department of Language & Communication is the study of child language development. Early language and communication skills have a key function for later school performance abilities and are closely related to other developmental areas. Especially with regard to early intervention and support of children with language developmental delays or disorders, the identification of factors influencing language development is highly relevant. Therefore, several years ago we started to build up a panel for a longitudinal study, which was financed by the German Research Foundation for the first six years and since then by budgetary funds. The long-term goal of this Dortmund longitudinal study is to identify those factors that have been shown to be predictive of the development of language and cognitive performance as well as of later school performance (such as mathematical ability). A group of approximately 40 children (growing up monolingual with German) is continuously observed in half-year and yearly steps since infancy (12 months old in 2012) and examined with regard to age-relevant abilities related to language.