Corpus research has revealed differences between the grammar of writing and the grammar of speaking, especially the grammar of everyday interaction. While much of the grammar of English is shared by writing and speaking, the differences show how spoken grammar responds to real-time, face-to-face interaction, with an emphasis on interpersonal choices. These factors are often represented in choices of tense and aspect, in the elaboration or reduction (ellipsis) of the grammar, word order, and so on. In this presentation, we look at real corpus examples of some of the features that make spoken grammar special and discuss why it should be a central part of the teaching of speaking and communication skills.