摘要:The present study investigated the priority of information among case particles, thematic roles or grammatical functions in determining the canonical SOV word order of written Sinhalese. Four types of sentences were given to native Sinhalese speakers to perform sentence correctness decisions. The active sentences with transitive verbs in Experiment 1 and with ditransitive verbs in Experiment 2 revealed that canonical sentences (i.e., SOV or SOOV) were processed more quickly and accurately than the scrambled sentences (i.e., OSV or OSOV), which supported the existence of scrambling effects. However, since thematic roles, case particles and grammatical functions provide the same information for the SOV canonical order, two further experiments were conducted to single out the priority of information. In Experiment 3, native Sinhalese speakers processed passive sentences with canonical word order defined by case particles (i.e., SOV) more quickly and accurately than those defined by thematic roles (i.e., OSV). In Experiment 4, native speakers processed potential sentences defined by grammatical functions (i.e., SOV) more quickly and accurately than the information provided by case markers (i.e., OSV). Therefore, the present study concluded that grammatical functions play a crucial role to determine SOV canonical order.