Covert Downward Entailment in Child English and Japanese*

English and Japanese differ in the interpretation of disjunction in simple negative sentences. However, the contrast vanishes in a ‘covert’ negative entailment created by the focus operator (only/dake). Experiments with English/Japanese children reveal their sensitivity to the interpretive interaction of disjunction with the focus operator, despite their divergent linguistic input. Our results suggest that disjunction is Boolean inclusiveor in both languages, because disjunction in both languages licenses conjunctive entailments under ‘covert’ negation. The findings also empirically support a nativist approach to the acquisition of semantics, with the semantics of natural language disjunction innately specified, rather than learned from experience.