Within the last decade systematic attempts to contrast different sociolects of a language have been undertaken which have important theoretical and practical implications on “contrastive linguistics.” One of the essential findings of such studies is the existence of systematic relationships between fluctuating variants, the structured variability captured in Labov's formulation of the “variable rule.” The notion of structured variability developed from studies in social lectology seems to provide an essential framework for contrasting different languages as well since it can capture the structured variability found in fluctuating interference variants. Both the static and dynamic aspects of this variation are discussed here, and practical considerations for future contrastive studies are su