This study investigates anaphora resolution in L2 European Portuguese by Italian and Spanish native speakers to
examine whether learners are sensitive to microvariation among these null subject Romance languages. Participants were 25 adult L1 EP
speakers, 69 L1 Italian, and 42 L1 Spanish adult learners of EP at three levels: upper–intermediate, advanced, and near-native.
They completed an untimed and a speeded multiple-choice task crossing the variables animacy of the matrix object
and type of embedded subject. Results indicate that sensitivity to microvariation develops as L2 proficiency
increases. However, learners’ performance remains permanently unstable in the areas where the L1 and the L2 differ, which is only
visible in the speeded task. Our findings challenge the idea that the L1 plays a minor role in anaphora resolution and have
implications for the Interface Hypothesis.