A discussion of English-speaking children's use of subjectless sentences contrasts the competence and performance explanations for the phenomenon. In particular, it reviews evidence indicating that the phenomenon does not reflect linguistic competence, but rather performance constraints. A tentative model of children's production is presented based on an integrated view of competence and performance to account for subjectless sentences as well as other language acquisition data. A group of 18 children with a mean age of 27 months were asked to imitate sentences in which subjects and objects were pronouns, proper names, or common noun phrases. The sentences were categorized according to meter. The children's omissions from the sentences indicate that, as predicted: (1) children omit subject pronouns more frequently than object pronouns or either proper or common noun phrases; (2) because subject articles always constitute a weak syllable in an iambic foot, they are omitted at the same rate as subject pronouns; and (3) object articles in sentences with a pronoun subject are omitted more frequently than object articles in sentences with proper or common noun phrase subjects and at the same rate as subject pronouns and subject articles. The results support the model's application. (MSE)