Disentangling sources of difficulty associated with the acquisition of accusative clitics in French

•3rd person accusative clitics (ACC3) are acquired later than 1st and 2nd person.•Three properties have been hypothesized to make ACC3 especially complex to acquire.•Morphological marking for gender has the strongest influence on ACC3 acquisition.•Optionality of ACC3 has a small, but detectible, role in its acquisition at age 4–6.•Discourse-participant independence of ACC3 only impacts its acquisition at age 4.

Accusative clitic pronouns are acquired later than both nominative and reflexive pronouns in typically developing French-speaking children. However recent research suggests that not all these clitics are equally difficult, 3rd person accusative clitics (ACC3) being more problematic than 1st and 2nd person. In this study, we explored three properties which could make ACC3 complex: (1) gender marking, (2) discourse-participant independent reference, and (3) optionality in spoken French. We have created specific experiments assessing the role of each of these properties in clitic acquisition in 41 French-speaking children aged 4–8. Results show that all three properties play a role in making ACC3 complex, with the strongest influence coming from gender marking. Implications of these results are discussed in light of previous related studies.