This introductory chapter starts by discussing how the areas of historical English linguistics, sociolinguistics, historical (socio)pragmatics and historical variation have changed in ways which now make a fruitful interaction between the fields possible, and it argues that it is useful to view the development of a variety such as Irish English from different prisms, combining new methods derived from the corpus-orientation of English historical linguistics, historical (socio)pragmatics and historical discourse analysis.

The chapter highlights the fact that research on regional variation from a historical perspective has remained largely unexplored until recently, and it argues that the study of different varieties of English can greatly benefit from longitudinal analyses that enable researchers with a better perspective of how these varieties have developed.

After providing an overview of the study of Irish English, the chapter introduces the reader to the use of historical corpora, such as the Helsinki Corpus of English Texts, the Penn Corpora of Historical English, the Corpus of Late Modern English Texts, ARCHER (A Representative Corpus of Historical English Registers), COHA (Corpus of Historical American English), CEEC (the Corpus of Early English Correspondence), CONCE (the Corpus of Nineteenth-Century English), etc. and it offers a general description of how Corpus Linguistics has contributed to the advancement of research into variation in English.

This chapter then describes CORIECOR, the Corpus of English Correspondence, which forms the basis of the book, and discusses its potential for the study of Irish English across time. While acknowledging the caveats that historical material present, the chapter argues for the validity of letters and discusses how private correspondence is a useful site for the study of orality in writing. In that sense, the chapter also draws attention to how the combination of research methods can be of interest to social historians as well as linguists.