This book aims to provide a micro-level, working model of a methodological approach and practical guidelines for building a corpus, informed by the work on the CorCenCC project (Corpws Cenedlaethol Cymraeg Cyfoes - the National Corpus of Contemporary Welsh). It focuses specifically on the development of detailed design frames for corpora across communicative modes (spoken, written and e-language), and the practical processes involved in the planning, collection, transcription, collation and (re)presentation of language data. The book is designed to be of significant value and relevance to those interested in critically engaging with corpus methodology. Although Welsh is the language under discussion, the processes and approaches discussed in the building of CorCenCC can be applied to a lesser or greater extent to other language contexts. This book provides a working model, and an account of how to build a corpus dataset from which step by step guidelines for creating other linguistic corpora in any language can be easily extrapolated. It will be of value to students and scholars of minority languages and corpus linguistics.