Case Alternation and Fragment Answers in Korean

This paper examines case alternation in Korean fragment answers as a diagnostic for the type of identity—syntactic or semantic—required for ellipsis licensing. The empirical landscape reveals a systematic division between impossible and possible case alternations. In impossible alternations—such as in the active or passive voice, oblique versus non-oblique realizations in <italic>spray/load</italic> constructions, psych-verb alternations, and periphrastic causatives—casemismatched fragments are uniformly disallowed, reflecting genuine differences in the underlying argument structure. Contrastingly, possible alternations—including direct causatives, <italic>siphta</italic> “want” constructions, goal versus ditransitive alternations, inalienable possession, lexical passives, and embedded subject constructions—freely permit case mismatch, insofar as the alternations do not correspond to distinct argument-structural configurations but instead arise from morphological or derivational variation within a single structure. These patterns collectively demonstrate that ellipsis licensing in Korean is determined by syntactic identity at the level of the argument structure rather than by semantic equivalence or surface case uniformity. Korean fragment answers thus provide strong typological support for structural approaches to ellipses (Merchant 2001, 2013; Chung 2013), showing that fragment interpretation is tightly constrained by underlying syntactic configuration even in the presence of rich morphological variation.