Languages employ different means to manifest the unaccusative-unergative distinction. In Mandarin Chinese, unaccusative verbs are allowed in the inversion construction “V-le NP”, while unergative verbs are not. This grammaticality contrast brings a presence/absence contrast between the two verb classes in the inversion construction in the input. Using an eye fixation task, we investigated whether Mandarin-learning 19-month-olds were sensitive to this specific input frequency contrast. We found that infants distinguished the grammatical versus ungrammatical uses of the two verb classes in the inversion construction “V-le NP” (Experiment 1). When the verb classes were in the “NP V-le” order (Experiment 2) (i.e., the same level of grammaticality), infants showed no evidence of a looking difference. These responses indicate toddlers’ sensitivity to the distribution of the two verb classes in the inversion construction. This distributional information is likely to be one of the potential cues that facilitate their acquisition of the unaccusative-unergative distinction.

Japanese has two types of two-place motion verbs whose ‘objects’ can be marked as either accusative or oblique (accusative–oblique alternations). The accusative–goal verbs mark their objects with accusative case -o or the goal marker -ni, and the accusative–source verbs mark their objects with accusative -o or the source marker -kara. Previous studies describe systematic differences in the interpretation of the arguments of these verbs and the events they denote between the two structures. This study argues that these alternating verbs are variable behavior verbs that are linked to two distinct syntactic structures. The core evidence for this claim comes from the results of two acceptability judgment experiments with Japanese native speakers that examined: (i) selectional restrictions on the subjects of the alternating verbs and (ii) the ability of their subjects to license ‘floating’ numeral quantifiers. The results of the experiments demonstrate that the accusative–source verbs alternate between the transitive and unaccusative structures, whereas the accusative–goal verbs consistently behave like transitive verbs but assign two different structural cases to their objects. Thus, the study shows that there are multiple ways in which two-place motion verbs are mapped onto distinctive syntactic structures, whereby the core meaning of the verbs and their syntactic structures together determine their interpretation.

This article proposes a hierarchy of functional heads encoding the features [±control], [±initiation], [±state], [±change] and [±telic] (see Ramchand 2008). It is argued that this allows for a superior analysis of split intransitivity in English than the traditional notion of ‘unaccusativity’ – the idea that there are two classes of intransitive verbs which differ in relation to the underlying status/positions of their arguments. Rather, it is shown – on the basis of a systematic consideration of a wide range of English verbs – that the proposed diagnostics for unaccusativity in English identify multiple classes, whose behaviour can be captured in terms of the proposed hierarchy. Good correlation is found between the classes identified by the English diagnostics and Sorace's (2000) Auxiliary Selection Hierarchy (ASH), providing further support for the cross-linguistic applicability of the ASH to split intransitive patterns.