For the historical linguist of English, Burney’s extraordinary body of extant prose presents an exciting opportunity to study idiolectal change and continuity in the eighteenth and nineteenth centuries. Burney’s long life, consistent writing habit, and large body of digitized text have enabled an idiolectal corpus of over 3 million words of prose to be compiled. This paper reports the findings of computational linguistic research conducted using this corpus, using statistical modelling to examine Burney’s use of dual-form adverbs. This modelling highlights Burney’s responsiveness to targeted linguistic prescriptivism, showing that she made widespread and persistent idiolectal reforms to an adverb paradigm highlighted in a 1796 review of Camilla by the Monthly Review. The modelling also reveals that this change did not spread by analogy to other adverb paradigms. These results highlight the potential for computational research to facilitate explorations into the extent, complexity, and nuance of Burney’s responsiveness to external stimuli, such as overt prescriptions or more subtle markers of sociolinguistic prestige.