Thesis (M.A.) from the year 2010 in the subject English Language and Literature Studies - Linguistics, grade: 1,5, University of Tubingen, language: English, abstract: It is a linguistic reality of todays world that English has become a lingua franca for the world. It is the global language of economy, technology, international politics, and the internet. In roughly 80% of communication in English, no native speakers are involved. As Smith/Nelson (1985) state: Native speakers are no longer the sole judges of what is intelligible in English (p. 1). Only recently, scholars in applied linguistics have conducted research on the characteristics of the use of ELF (English as a lingua franca) in interactions between non-native speakers of English. For the purpose of ELF research, large corpora such as VOICE (Vienna-Oxford International Corpus of English) have been built up, containing data from naturally occurring ELF exchanges. Also at the University of Tübingen a corpus of this kind is currently being compiled: the Tübingen Midwestern Corpus, which contains group discussions on a given economic topic. Most of the discussion participants are international students with different first language backgrounds. Some discussions also include a native speaker of English. There has to date not been a uniform and systematic approach regarding the analysis of comprehension problems in these Midwestern discussions. In this thesis I will design a structured set of questions for a standardized retrospective interview that serves to efficiently analyse comprehension problems. As the investigation of comprehension problems must go beyond an analysis of purely linguistic features of an interaction (syntax, morphology, phonology), situational circumstances in which the interaction takes place will also be taken into account. These standardized retrospective interview questions will be applied to four group discussions taken from the Midwestern corpus. For the analysis of the data collected from the retrospective interviews with participants from these discussions, Relevance Theory and discourse analysis are going to be applied.