The purpose of this chapter is to provide a two-dimensional approach to language documentation (Hi mmelman 1998). In addition to building a database, we also conducted a sociolinguistic survey des igned to document the state of health of a language in a particular spatio-temporal frame. Our goa l is to share our fieldwork experience of documenting Kavalan, a seriously endangered language in sou theastern Taiwan now spoken by fewer than just a few dozen speakers. We first discuss our field exp eriences in working with speakers of Kavalan in Sinshe village, the only significant Kavalan set tlement left in Taiwan, and the state of the Kavalan language, based in part on Huang and Cha ng’s (19 95) earlier sociolinguistic survey, and in part on a recent more in-depth village-wide survey of lan guage use in the community. Next, we introduce the NTU Corpus of Formosan Languages, part of which incorporates our corpus data in Kavalan. The NTU Corpus of Formosan Languages aims to establish a standard for the creation of linguistic corpus databases through the application of information technology to linguistic research. The creation of this linguistic database enables us both to preserve valuable linguistic data and to provide a systematic recording of these languages, for the benefit of future linguistic research.