The development of infinitives by three, four, and five-year-old children

The present study investigated children's knowledge of infinitival complements with respect to control and knowledge of subcategorization constraints for object Noun Phrases and complementizers. The experimental tasks included a story completion task designed to elicit productions of infinitival complements; an act-out comprehension task; and a grammaticality judgment task. Twenty-seven children between the ages of 3 years; 7 months and 5 years; 4 months participated in the study.;With respect to the referent of PRO, the subject of the complement clause, fifteen children allowed arbitrary reference on (NVtoV) sentences with at least one matrix verb that would require subject control in adult English. Fifteen children allowed either mentioned NP to be the antecedant of the complement subject in (NVNtoV) sentences with at least one matrix verb. Six of these children allowed either antecedant with want-type verbs and, therefore, showed overgeneralization of an analysis involving a PRO complement subject to verbs that require a lexical complement subject in adult English. There were also three children identified who did not use control principles to interpret the complement subject. These latter three children allowed arbitrary reference for PRO on (NVtoV) sentences and only produced (NVNtoV) sentences with a lexical complement subject.;These results were related to overgeneralization and verb-specific learning as processes in language acquisition. The relevance of both linguisitic theory and empirical data in the study of language acquisition was discussed. The adequacy of act-out comprehension tasks for studying children's knowledge of language was questioned.;The production task proved to be successful in eliciting infinitival complements. Children varied in their willingness to produce an infinitival complement with an unfamiliar matrix verb. The children were generally conservative in their use of object NPs. No child produced an object NP with a matrix verb not subcategorized for object NPs. In contrast, there were (Noun-Verb-to-Verb) productions with matrix verbs that require object NPs by four of the younger children with the familiar verb tell and by children of all ages with the unfamiliar verb force. For complements were produced mainly by the older children and were used with matrix verbs not subcategorized for the for complementizer.