Accounting for register-internal variation

Registers are text varieties associated with situations of use. It has now been documented, however, that texts within registers are not situationally homogeneous — just as they are not linguistically uniform. This led Biber and Egbert (2023) to propose that linguistic variation within registers functionally corresponds to situational variation among their texts. The situational factor consistently shown to vary within registers is communicative purpose. However, previous studies have examined variability in purpose within a single register and always relied on coding schemes developed for that register. As a result, there is no single taxonomy of communicative purposes to be applied across registers. This paper proposes such a framework, offering guidance for its future adaptations to other corpora, and demonstrates how its application enables (a) analyses of functional correspondence between communicative and linguistic variation among texts of several registers; (b) register comparisons for the extent of internal variation.