Morphological systems have been pivotal in exploring cognitive mechanisms of language use and acquisition. Adult English definite article form preference seems to depend non-deterministically on multiple factors. A corpus study of adult spontaneous speech revealed similar patterns of variability. In an experiment, article variant preferences of three age groups were compared. Children were sensitive to the same phonological factors as adults, but showed effects of more limited experience with articulation and orthography. Preferences across age groups suggest developmental changes, but no evidence that children initially use a default form. Corpus studies of children's and adults' speech also revealed no evidence for a default. The results point to overgeneralisation of both article variants, resulting from extended competition between variant forms. (Contains 6 tables, 2 figures, and 3 footnotes.)