Verb-marking errors such as "she play football" and "daddy singing" are a hallmark feature of English-speaking children's speech. We investigated the proposal that these errors are input-driven errors of commission arising from the high relative frequency of subject + unmarked verb sequences in well-formed child-directed…

There is substantial evidence that children's apparent omission of grammatical morphemes in utterances such as "She play tennis" and "Mummy eating" is in fact errors of commission in which contextually licensed unmarked forms encountered in the input are reproduced in a context-blind fashion. So how do children stop making such…