“…A large body of work investigated how toddlers and young children produce morphologically complex forms, starting with Berko's (1958) famous wug-test, showing for the first time experimentally, young children's productive and generalized use of morphological rules. Similar investigations in Hungarian (Gósy, 1984;MacWhinney, 1975MacWhinney, , 1976Pléh et al, 2002;Réger, 1979) have also shown that pre-schoolers and schoolaged children productively apply morphological rules, with the U-shaped developmental trajectory also found in other languages, whereby in the early stages of production, irregular forms are produced correctly from rote memory, then rules are overgeneralized and irregular forms get regularized as a result, finally the irregulars emerge again correctly. In accordance with the dual-process hypothesis, different stem categories show different developmental timing.…”