Sometimes descriptions of known facts about a language fail to be explanatory in a satisfying way, because they ignore parallelisms in related languages, including chronologically earlier stages of the same language. This article examines several Romance languages and dialects in terms of similarities in morphological evolutionary development. Consideration of comparative data indicates that the polarization of standards can overlay similar patterns of variation in different regions and that an explanatory description of nonstandard usage needs the added dimension offered by use of comparative and historical data. (Author/DB)