Abstract
This paper examines, on the basis of a corpus study, how and why the modern intransitive-transitive system of Sino-Japanese verbs (Chinese loan words + the Japanese light verb -suru) has greatly changed over time. The conclusions are as follows: 1) Modern Sino-Japanese verbs can be used transitively when they represent changes in which agents are not restricted to humans (or animals); they can be used intransitively when they represent changes which come about without external human control. When both of these conditions are satisfied, they can be used both intransitively and transitively. 2) In this intransitive-transitive verb system of Sino-Japanese, only some of the verbs that have both intransitive and transitive usage have changed. These changes come in two directions: one is to lose transitive usage, and the other is to lose intransitive usage. The former happened as a condition of having transitive usage became more "severe" (verbs which express events that are likely to occur spontaneously cannot have transitive usage) due to assimilation to native Japanese verbs, many of which have a pair of different forms for intransitive and transitive verbs. The latter happened because certain verbs narrowed their semantic field to denote only events for which external human control is necessary. 3) Of these two, the verbs which have lost transitive usage greatly outnumber those that have lost intransitive usage. This can be explained through the native Japanese suffix -saseru functioning as a "causative" marker, substituting for the former transitive usage, whereas there is no "anti-causative" marker in Japanese (the passive marker -sareru does not function as "anti-causative").
