AbstractThe study of causal influences onmarked disorders of speech and language have been dominated by dichotomies and reductionist models. However, the emergent evidence of epigenetics forces us to acknowledge the complex mecha-nisms that underlie such conditions. The purpose of this article is to highlight future directions for studying the causal mech-anisms that underlie children’s speech and language disorders, with an emphasis on speech sound disorders and specific language impairment. In doing so, we will briefly highlight past methods of studying genetic effects on children’sspeech sound and language disorder profiles and propose the dynam-ic systems theory as a meaningful framework for studying the complex landscape of childhood speech-language develop-ment. This model challenges traditional dichotomies between genetic and environmental effects and between beneficial versus deleterious effects/factors. KeywordsSLI.SSD. epigenetics. Developmental Systems Theory. Candidate genes