Universal patterns in the acquisition of negation and disjunction: Parallels between L1 and L2

A fundamental question in language acquisition is how learners balance input and prior knowledge to infer meaning. Here, we present novel evidence about the mechanisms guiding adults' second language learning. We examined their interpretation of disjunction ("or") in negative sentences (e.g., "John didn't eat the cucumber or the pepper") as a test case. Languages vary in the assignment of scope to logical operators such as negation and disjunction, depending on their syntactic relationship. When multiple interpretations are possible, how do learners assign meaning? Does the native language of L2 learners influence this process? We report three key findings. First, native speakers of Mandarin and Spanish prefer an interpretation where "or" scopes over negation, meaning "John ate either the cucumber or the pepper, but not both" (the "not both" superset interpretation), whereas L2 learners from both backgrounds favor the opposite, subset (stronger) interpretation, where "John ate neither vegetable" (the "neither" subset interpretation). This pattern resembles child first language acquisition. Second, this preference persists even when the surface order of negation and disjunction does not match the native speaker's preferred interpretation, indicating that learners reconstruct underlying structure during interpretation, rather than rely on surface cues. Third, this tendency is stronger in less proficient learners and shifts with increasing proficiency. These findings suggest that L2 learners employ strategies similar to those of children acquiring their first language, initially favoring the stronger possible interpretation. These results shed new light on universal mechanisms guiding both first and second language acquisition.