This study presents CILLCO (Corpus of Indonesian Language, Linguistics, and Communities), a digital corpus designed to document and analyze vernacular language varieties in everyday and digital contexts. Jointly established by the Research Center for Language, Literature, and Community at the National Research and Innovation Agency (BRIN) in collaboration with the English Department of Universitas Islam Indonesia (UII), CILLCO addresses the historical gap between the national standard language (Bahasa Indonesia baku) and its vernacular varieties at the interpersonal, media, and online levels across the Indonesian archipelago. While most existing Indonesian corpora focus on written and formal language, CILLCO focuses on naturally occurring communication, capturing data such as WhatsApp exchanges and everyday conversations. As such, CILLCO functions as a linguistic and communicative resource platform, providing researchers with empirical materials to examine how meaning is made, identities are negotiated, and social relations are enacted in the hybrid spaces of spoken and digital communication. The corpus incorporates multimodal sources, including spoken discourse, social media interactions, online conversations, web documents and comments, transcribed interviews, and regional narratives, all encoded through sophisticated annotation and retrieval tools. By embedding CILLCO within current work in corpus linguistics, communication research, and digital ethnography, this study demonstrates the corpus's potential to advance interdisciplinary investigation into language use, digital discourse, and sociocultural change in Indonesia. CILLCO offers a solid empirical foundation for analyzing communicative practices in Southeast Asia, contributing to decentered, corpus-driven communication research. Ultimately, it sheds light on how digital vernacular communication reshapes the linguistic landscapes and communicative identities of Indonesian speakers in an era of rapid digital transformation.