Acquiring the features of negative indefinites

Abstract Corpus-based and experimental studies show that children acquiring non-Negative Concord (NC) languages often display NC-like behaviour, producing or interpreting sentences with two negatives as a single negation. Previous work has taken this as evidence that children initially posit a non-target NC grammar (e.g., Sano et al., 2009 ; Thornton et al., 2016 ; Nicolae & Yatsushiro, 2022 ; Driemel et al., 2023 ; Illingworth et al., 2025 ). The empirical basis for this claim is, however, largely based on Double Negation systems, especially Germanic. This paper presents the first corpus study of NC and negative indefinites in Catalan and Spanish, supplemented by existing and new Italian data. Comparison with Romance and Germanic reveals differences in error rates, age of emergence, and error types, providing evidence that challenges the view that NC is children’s ‘developmental default’. I argue that these findings are more readily captured under Zeijlstra’s (2004) Agree-based approach to NC.