In this article I begin by presenting some examples from Early-Modern French of how, using a large multi-genre database (Frantext), it is possible to track the spread of change and how it embeds across different genres (the genres in Frantext ranging from correspondence and first-person travel narratives to essays and poetry). These case studies allow us to explore a number of questions, including which changes seem to diffuse “from above” and which rather come “from below”; and which textual sources best reflect “authentic” usage or indeed are closest to reflecting spoken usage. They also raise questions as to whether it is possible to create a continuum of genres with those that are more “progressive” or are early adopters of change at one end, and those which are more resistant to change at the other. I then discuss some of the challenges surrounding this work, including the theorization (or lack of theorization) of text types and genres in various corpora and the privileging of other factors when they are elaborated. Consequently, there is currently a lack of comparability between different corpora in the way they categorize and calibrate different text types and genres.