This paper presents a quantitative analysis of the variation underlying subject-verb agreement in the spoken French interlanguage of Irish classroom and study abroad learners. Results outline the range of factors constraining that variation, such as the learners' level of informal contact with the language, as well as linguistic factors such as temporal context, verb frequency, and functional constraints. Since the variation observed is specifically restricted to irregular verbs in third person plural contexts, the findings are discussed with reference to the acquisition of (ir)regular verb morphology.