The Development of Basque Subject Pronoun Expression in Bilingual School-Age Children

Acquiring full mastery of the pragmatic constraints regulating null/overt pronominal subjects in null subject languages like Basque is a prolonged and cognitively taxing process because pronominal distribution is pragmatically conditioned in discourse. The purpose of this study is to elucidate the acquisition of subject pronoun expression (henceforth, SPE) by school-age Basque-speaking children because Basque has a gender-neutral third-person singular pronoun (bera) with a different pronominal feature configuration than traditional pronouns in other languages, which may impact how SPE is acquired. Therefore, we report on a study investigating the acquisition and development of the personal pronoun bera in 88 Basque-Spanish bilingual children (ages 6-12) and adults, using an oral pronoun elicitation task where null subjects and the overt pronoun bera were elicited in same- and switch-reference contexts. Findings indicate that bilingual children follow a U-shaped developmental trajectory in same-reference contexts in Basque, which favor null subjects, but a linear developmental trajectory in switch-reference contexts, which favor bera. These findings are consistent with previous work on the same Basque-Spanish bilinguals who participated in the present study tested in Spanish and age-matched Spanish monolinguals (Etxebarria & Montrul 2025), who showed parallel and age-appropriate developmental trajectories. Results revealed that null subjects encode strong referential continuity properties in Basque. However, bera seems to have more flexible referential discontinuity properties than traditional third-person pronouns, likely due to its intrinsic feature composition and referential properties. These results also support the conclusion that pronoun distribution is variable in null subject languages (Giannakou 2018; Otheguy & Shin 2022; Etxebarria & Montrul 2025).