While discourse markers have been examined in some detail, little is known about their usage by non-native speakers. This book provides valuable insights into the functions of four discourse markers (so, well, you know and like) in native and non-native English discourse, adding to both discourse marker literature and to studies in the pragmatics of learner language. It presents a thorough analysis on the basis of a substantial parallel corpus of spoken language. In this corpus, American students who are native speakers of English and German non-native speakers of English retell and discuss a silent movie. Each of the main chapters of the book is dedicated to one discourse marker, giving a detailed analysis of the functions this discourse marker fulfills in the corpus and a quantitative comparison between the two speaker groups. The book also develops a two-level model of discourse marker functions comprising a textual and an interactional level.