To What Extent Does Split Intransitivity of the Adult Target Affect Children’s Emerging Verb Patterns?

The Unaccusative Hypothesis has produced several diagnoses for determining whether a given intransitive verb is unaccusative or unergative. While some are suggested to be language-specific, like ne in Italian or pleonastic “there” in English, others have a wider application, such as the distribution of BE and/or HAVE as the perfect auxiliary. The distinction, or not, of HAVE/BE auxiliaries in adult input would arguably have major implications for children acquiring their first language, particularly in terms of the acquisition of the notion of split intransitivity. Languages like Italian, Dutch, or French which make the auxiliary distinction would seem to provide greater transparency to children in terms of split intransitivity while others like English or Spanish would be less transparent because they utilize only HAVE, although earlier versions of these languages are attested to have also possessed at one time both auxiliaries. This study draws on four CHILDES data sets to compare the early emergence patterns of intransitive verbs in four monolingual children (two from each language) learning Spanish and Italian. Cross-linguistic observations of the data include: 1) an initial predominance of unaccusative verbs at the one- and two-word stages; and 2) particular morphology corresponding to early verb types, namely, initial preference for third-person, singular, past tense verb forms with unaccusatives and the singular imperative with unergatives. The study concludes that, despite an apparent lack of transparency in adult Spanish language input, monolingual children learning Spanish may demonstrate a comparable degree of early sensitivity to split intransitivity as their monolingual counterparts who are exposed to adult Italian, attributing the similarity to inherent structural differences between unaccusatives and unergatives and Universal Grammar