ABSTRACT
In both written and spoken forms, the Sinhalese language allows all six possible word orders for active sentences with transitive verbs (i.e., SOV, OSV, SVO, OVS, VSO, and VOS), even though its unmarked order is subject-object-verb (SOV) (e.g., Gair, 1998; Miyagishi, 2003; Yamamoto, 2003). Reaction times for sentence correctness decisions showed SOV < SVO = OVS = OSV = VSO = VOS for the written form, and SOV < SVO = OVS < OSV = VSO = VOS for the spoken form. The different degrees of reaction times may correspond to the three different types of word order alternation. First, the fastest reaction time for SOV word order corresponds to the canonical order SOV without any structural change, represented as [ TP S [ VP O V] ] for both the written and spoken forms. Second, word order alternation at the same structural level is involved in both SVO and OVS, [ TP S [ VP t1 V O1] ] for SVO and [ TP t1 [ VP O V ] S1 ] for OVS, resulting in a slower reaction speed than SOV. Third, and again for only the spoken form, word order alternation takes place at a different structural level, [ TP’ O1 [ TP S [ VP t1 V ] ] ] for OSV, [ TP’ V1 [ TP S [ VP O t1] ] ] for VSO, and double word order alternations take place within the same level as [ TP t1 [ VP t2 V O2 ] S1] for VOS. These word order alternations for OSV, VSO and VOS require an extra cognitive load for sentence processing, even heavier than for a single word order alternation of SVO and OVS taking place at the same structural level. The present study thus provided evidence that the speed of sentence processing can be predicted from the cognitive load involved in word order alternation in a configurational phrase structure.