AbstractUnderstanding how spoken language is represented in novels over time is a key question in the Digital Humanities. We propose a new metric for characterizing spoken dialogue in the novel, called dialogism, that instantiates Bakhtin’s claim that all texts are fundamentally dialogic. This measurement uses abstract grammatical features in a span of text (such as the use of pronouns, mood, or subordinate clause structure) to measure the extent to which the span is dialogic, i.e. exhibits the grammatical structures common to natural spoken dialogue. We use this metric to explore the dialogism of 1,100 largely canonical English novels over 230 years. We combine quantitative and qualitative investigation of the dialogic properties of both dialogue and narration to show novel stylistic properties of literary innovation during three periods: the late 18th century, the turn of the 19th century, and the mid-20th century. We find that during these moments, certain authors reject literary conventions by changing the dynamic between the narrative and dialogue portions of the texts. Our analysis shows that these changed dynamics are behind rises in persuasive writing, reflections of psychological processes, and the use of dialogue as an increasingly important driver of the novel as a whole. These results show that computational models that characterize style grammatically, generalizing across time and genre, can lead to literary and methodological insights.