This is the first special issue of Modernism/modernity, the official journal of the Modernist Studies Association, to focus on South Asia. Co-edited with Preetha Mani (Rutgers University) and featuring an afterword by Rebecca Walkowitz (Barnard College), the issue argues that South Asian modernisms cannot be understood without reference to South Asian language politics, in particular processes of vernacularization (by which South Asia's many vernaculars were standardized, communalized, minoritized, and monolingualized in the 19th and 20th centuries, and new hierarchies established between these languages). With articles on modernist writing in Urdu, Hindi, English, Marathi, Maithili, Bengali, and Tamil, the issue shows how language itself--porous and unstable--becomes the unrepresentable to which modernism struggles to give form.