In 1979 and 1980 I set about recording a variety of classrooms where English was being taught as a foreign language. My purpose was to develop a method of analysing and describing the language used in foreign language lessons in such a way as to enable objective comparisons to be made between the discourse resulting from different classroom activities and different teacher styles. This research, based on an adaptation and extension of the Sinclair and Coulthard (1975) model, is fully reported in J. Willis (1981). In this chapter, I shall concentrate on one basic concept in that research, which I hope will help to shed light on how language is used by teachers and students in language teaching classrooms. Implications and adaptations for the more ‘communicative’ classrooms of the 1990s are also discussed.