This study has two goals: first, to investigate prior language influence in the acquisition of object pronominalisation in the third language (L3) French by speakers whose first language (L1) grammar allows null objects; and, second, to find out whether non-native behaviour in relation to object pronominalisation is modulated by task type. I compare L3 speakers of French whose L1 is Sinhala and L2 English with L2 speakers of French whose L1 is English. Sinhala allows null objects, whereas null subjects are not allowed in French and English. Using data from a speaking task and acceptability judgement tasks, I found that the L3 speakers omit objects in production while demonstrating knowledge of the obligatory nature of French clitic pronouns in comprehension. The proficiency-matched L2 speakers, by contrast, do not omit objects. Drawing on Amaral and Roeper’s (2014) Multiple Grammars account of multilingual knowledge, I argue that the increased processing load of the production task compared with the comprehension task leads to the L3 speakers resorting to structures available in their L1. While the L2 speakers may also resort to L1 structures under increased cognitive load, their L1 does not include null objects, hence null objects do not arise in the L2 group.
