In simpler terms, Ernst Haeckel's claim that "ontogeny recapitulates phylogeny" means that the development of an individual summarizes or mirrors the development of a species. While discredited as a biological theory, some linguists still use it these days to argue that language development in a child sums up or mirrors language development in early people.
In 1866, Ernst Haeckel proposed the idea that "ontogeny recapitulates phylogeny." …
