Subject-verb (SV) agreement helps listeners interpret the number condition of ambiguous nouns (The sheep is/are fat), yet it remains unclear whether young children use agreement to comprehend newly encountered nouns. Preschoolers and adults completed a forced choice task where sentences contained singular vs. plural copulas (Where is/are the [novel noun(s)]?). Novel nouns were either morphologically unambiguous (tup/tups) or ambiguous (/geks/ = singular: gex / plural: gecks). Preschoolers (and some adults) ignored the singular copula, interpreting /ks/-final words as plural, raising questions about the role of SV agreement in learners' sentence comprehension and the status of is in Australian English.
Keywords: agreement; comprehension; language change.