Children acquiring a non-negative concord language like English or German have been found to consistently interpret sentences with two negative elements in a negative concord manner as conveying a single semantic negation. Corpus-based investigations for English and German show that children also produce sentences with two negative elements but only a single negation meaning. As any approach to negative concord and negative indefinites needs to account for both the typological variation and the child data, we revisit the three most current syntactic Agree-based analyses, as well as a movement-based approach and show that they either have difficulties with the child data or face challenges in the adult language variation or both. As a consequence, we develop a novel analysis of negative concord and negative indefinites which relies on purely morphological operations applying to hierarchical semantic representations within a version of the Meaning First architecture of grammar. We will argue that the typological variation between the main three different types of languages as well as the children’s non adult-like behaviour fall out from this in a straightforward fashion while the downsides of the Agree- and the movement-based accounts are avoided. ; European Research Council (ERC) ; Peer Reviewed