Using Corpora to Explore Linguistic Variation illustrates the ways in which linguistic variation can be explored through corpus-based investigation. Two major kinds of research questions are considered: variation in the use of a particular linguistic feature, and variation across dialects or registers. Part 1: "e;Exploring variation in the use of linguistic features"e; focuses on the study of specific words, expressions, or grammatical constructions, to study variation in the use of a particular linguistic feature. Part 2: "e;Exploring dialect and register variation"e; describes salient characteristics of dialects or registers and the patterns of variation across varieties. Part 3: "e;Exploring Historical Variation"e; applies these same two major perspectives to historical variation. One recurring theme is the extent to which linguistic variation depends on register differences, reflecting the importance of register as a key methodological and thematic concern in current corpus linguistic research.