The roots of root infinitives: remarks on infinitival main clauses in adult and child language

The past decade has produced various theories for explaining why children learning certain languages will often use infinitival utterances. One class of these approaches shares the property that a period in language acquisition is assumed during which the marking of finiteness on the verb is optional in the children's grammar. In these theories, finiteness marking on the verb is considered obligatory in the corresponding adult languages. Another class of acquisition accounts attributes infinitival main clauses to processing overload. I argue here that both types of theory are insufficient, because they are based on ill-conceived assumptions about adult languages. Consequently, they make inadequate predictions about children's linguistic behavior SUBSEQUENT to the so-called optional-infinitive stage. In the final section, I sketch out the ingredients of an approach to infinitival utterances that promises to explain not only why children use them in relatively large proportions, but also how they get rid of some of them, while keeping the option of using them, as is required in the target languages.