This paper examines the suggestion that infinitivaltoomission errors in English-speaking children can result from competition between two constructions (Kirjavainen et al., First Language 29: 313–339, 2009a). Kirjavainen et al. suggested that the acquisition of two (or more) constructions (e.g., WANT-X and WANT-to) for verbs takingto-infinitival complement clauses can lead to infinitivaltoomissions, reflecting the relative frequencies of the constructions in the input. In the present study we analysed 13 English children's corpora to determine whether the presence of a variety of utterance (...) types in the immediate discourse context preceding WANT-to-VP (e.g.,I want to eat it) and erroneous *WANT-zero-VP (e.g., *I want__drink it) constructions was associated with infinitivaltoproduction/omission. This was done separately for the children's own and their interlocutors' discourse utterances. The data show that the occurrence of WANT-toand WANT-X constructions in the prior discourse was associated with differing proportions of infinitivaltoprovision in the WANT-to/zero-VP construction. This together with Kirjavainen et al.'s (First Language 29: 313–339, 2009a) data suggests that children are learning at least two constructions for the verb WANT, that competition contributes to infinitivaltoomissions, and that the strength of competing representations is affected by overall input frequencies and the preceding discourse. (shrink)