The nominative/accusative alternation in Japanese and information structure

In Japanese, desiderative (and potential) predicates derived from transitive verbs allow their direct object to be marked with the nominative marker ga, instead of the expected accusative marker o. This article argues that the nominative/accusative alternation in a desiderative construction has an information-structural implication. Nominative-marking on the object indicates its focushood, i.e., that it is either the focus of the utterance or part thereof, whereas accusative-marking has no such information-structural bearing. This claim is motivated by the observation that the direct object of a desiderative predicate resists nominative-marking when it is not adjacent to the predicate ("adjacency effect"). Under our account, the adjacency effect can be regarded as a variety of the garden-path effect, stemming from the discrepancy between the default (expected) locus of the focus and the pragmatic information conveyed by nominative-marking. With three sets of experimental data (from two acceptability judgment experiments with written stimuli and one rating experiment with auditory stimuli), we demonstrate that (i) the adjacency effect is real, and (ii) it can be mitigated by prosodie or contextual cues signaling the focushood of the object. The second finding conforms well to our hypothesis that the adjacency effect is a processing-based phenomenon, rather than a reflection of a purely syntactic constraint.