Stepping into the same river twice on the discourse context analysis in the LANCHART project Frans Gregersen a *, Søren Beck Nielsen a and Jacob Thøgersen b a The LANCHART Centre; b Centre for Internationalisation and Parallel Language Use, University of Copenhagen (Received 21 July 2008; final version received 8 September 2008) The question of comparability in sociolinguistic studies is both obviously methodologically crucial and rarely addressed. If not addressed at all in sociolinguistic investigations of language change in real time, the analyst will invariably run the risk of comparing inherently different pieces of data material. But the question is, whether it is at all possible to achieve comparability? In this paper we argue that methodological considerations of comparability are necessary ingredients in any study of change in real time, and we present the apparatus used to achieve comparability in the LANCHART study, viz. the so-called Discourse Context Analysis (DCA). The DCA is the basis for the phonetic analysis in the LANCHART study since it selects maximally comparable sections of passages for analysis. However, in this paper it is also shown to function as a fruitful analytic tool in its own right, illuminating changing interactional patterns in sociolinguistic interviews which are likely to reflect changes in how people interact with one another in society at large. Keywords: language variation and change; comparability; discourse context; interaction analysis You cannot step into the same river twice Heraclitus 1. Introduction All investigations of language change in real time involve at least two different studies, in the following called S1 and S2. S1 and S2 may diverge in a number of ways but they necessarily have to stem from two different points in time. The LANCHART project thus compares S1s with S2s. Due to the historical coincidence that the Danish Research Council for the Humanities in 1986 launched a five year project on Spoken Danish in its varieties, the majority of the LANCHART S1 studies stem from the middle of the 1980s and thus belong at the same point in time. This means that the distance in time between S1 and S2 in the LANCHART project is 20 years since the S2 recordings began 2005 and ISSN 0374-0463 print/ISSN 1949-0763 online q 2009 Taylor & Francis DOI: 10.1080/03740460903364045 http://www.informaworld.com *Corresponding author. Email: fg@hum.ku.dk Acta Linguistica Hafniensia Vol. 41, November 2009, 30–63