This project is a sociolinguistic history of vernacular Malay, the language of and for society in pre-independence Indonesia. This non-standardized form of Malay was used by the ethnically diverse, rudimentary educated urban lower middle-class - a large demographic niche that occupied the forefront of modernity. A substantial body of literature is available on this vibrant world, yet the linguistic character of these sources is not well-known. A study on the history of this language is crucial to understand how its speakers experimented with new concepts, ideas and knowledge, and how this affected Indonesias sociocultural history. What were the characteristics of vernacular Malay? Who were involved in shaping the mixed language and culture of Indonesias colonial cities? What desires and anxieties emerged in this society and how were they expressed in the vernacular Malay literature? The central objective of this research is to analyse a voluminous collection of digitized Malay books and newspapers (1870s-1930s). These writings offer vivid depictions of the language and society of Indonesias oft-neglected urban populations in late-colonial times. This project will produce a monograph-length sociolinguistic analysis and an online, publicly available database of this body of literature. Digital access to these primary sources facilitates quantitative cross-validation of qualitative research. Consequently, I will be able to generate a robust evidential base and reveal patterns previously opaque. Based on the sociolinguistic expertise of the researcher, this project aims to gain insight into the history of everyday life in an ethnically diverse society at the crossroads. The characteristics of a non-standardized language, the origins of its vocabulary, and its role in the designation of new ideas and concepts will provide a multifaceted picture of a nations colonial roots and its legacies for the present, in which the non-elite and the culturally hybrid can finally assume their rightful place.