Skilled and impaired language users can fail to understand sentences with noncanonical thematic role ordering. To advance understanding of the cause of the difficulty, we compared noncanonically ordered, object-experiencer-verb (OE) sentences to canonical agentive sentences in otherwise comparable syntactic structures. However, the field has neglected to consider that OE thematic roles may be altered by the comprehender’s interpretation; the aim of the investigation reported here was to address this research gap. We collected participants’ thematic role interpretations for sentences while measuring incremental processing speed as they read the sentences in a self-paced reading paradigm. Fluent English speakers rated the intent of the subjects of OE and agentive active sentences and of the objects of OE and agentive passive sentences. Consistently high ratings of intent identified a cluster containing agentives and an OE eventive subtype with an agent. In contrast, a spread of ratings in a second cluster suggested labile interpretation for a second OE subtype. Splitting the labile group at its active and passive mean, we compared reading time of OE and agentive sentences with a higher-intent, agent interpretation with OE sentences with a low-intent causer/theme interpretation. Whether active or passive, canonicity as determined by the relative prominence ordering of the rated role compared to the necessary OE experiencer or agentive theme, accounted for reading speed at the verb, second noun, and prepositional phrase. We propose that the results support an agent > experiencer > (causer)/theme thematic role hierarchy, suggesting refinements to event structure theory and little v/CAUS morphology.