The goal of the paper is to demonstrate how sociolinguistic research can be applied to endangered language documentation field linguistics. It first provides an overview of the techniques and practices of sociolinguistic fieldwork and the ensuring corpus compilation methods. The discussion is framed with examples from research projects focused on European-heritage English-speaking communities in the UK and Canada that have documented and analyzed English dialects from the far reaches of Scotland to the wilds of Northern Ontario, Canada. The main focus lies on morpho-syntactic and discourse-pragmatic variation; however, the same techniques could be applied to other types of variation. The discussion includes examples from a broad range of research studies in order to illustrate how sociolinguistic analyses are conducted and what they offer for understanding language variation and change.