The first case study in this chapter continues the concern with different meanings of very frequently spoken words developed in the previous three chapters. It examines and compares the production of discourse markers by native and non-native speakers of English based on a pedagogic sub-corpus from CANCODE, a corpus of spoken British English which was drawn on for discussion in chapters 1 and 3. It is contrasted with a spoken corpus of interactive classroom discourse of English-speaking secondary pupils in Hong Kong. It will be noted that many of the most frequently spoken words in the language (as indicated in chapter 1 and in part in chapter 2) come into the category of discourse marker. Language development has been undoubtedly aided by corpus-informed studies and by the applications of corpus linguistics to pedagogic contexts, but it has tended to be confined to the development of writing and reading. The main applied linguistic purpose here is to underline that the teaching and learning of spoken English can be advanced by spoken corpus development and use.