In Chapters 4 and 5, we focus on the smallest component of the interactional grammar: expressions. Chapter 4 presents a way of analysing and describing expressions which are meant to lubricate the flow of interaction. The acquisition of such expressions is very important for learners, who need to be made aware of their use. We define this category of expressions as Gambits. While it is a popular assumption that Gambits – often called ‘discourse markers’ in the literature – are devoid of meaning, we shall show that this is far from being the case.