This paper explores how five key complementary features of variable systems—overall rates, variant conditioning, productivity, contextual dispersion, and diffusion in the community—must be marshaled to provide a more comprehensive characterization of change in progress. We illustrate by revisiting a robustly variable sector of Canadian French morphosyntax whose variants are known to be in flux: the polar interrogative domain. Analyses extend the timeline of Elsig (2009)/Elsig and Poplack’s (2006) diachronic analysis by an additional twenty-five years, bringing 2,000+ questions produced by 133 speakers to bear on developments occurring over a period of nearly a century and a half of spontaneous Québec French speech. Results underscore the need to consider more than rates and conditioning in the study of language change. Linguistic dispersion and diffusion in the community provide crucial insight into the mechanics of the transition period and contribute to identifying shifts in variant productivity at each point in time.
