When Differential Object Marking is Optional: The Case of Copala Triqui

In Copala Triqui, an Otomanguean language of Oaxaca, Mexico, the presence of the accusative marker is triggered by factors pertaining to animacy and specificity (Broadwell 2022), which is common for languages with differential object marking (DOM, Silverstein 1976; Comrie 1989; Kalin 2018). This paper investigates optionality in Copala Triqui DOM, specifically as it pertains to the marking of non-human animate direct objects as participants of reversible events. Copala Triqui exhibits both VSO and SVO word orders, raising the question of how DOM and word order interact. We present a 2x2 speeded acceptability judgment experiment that crossed two factors: the presence/absence of accusative marking and VSO/SVO order. Our results show an interaction of word order and accusative marking, with presence of DOM hindering an “acceptable” response for VSO. We also found that different groups of speakers responded differently to the presence of DOM in SVO clauses: only the youngest speakers responded more quickly to SVO clauses with DOM than those without. We consider how language shift in this largely bilingual population might contribute to response time variability.