Spoken registers differ from written registers in several fundamental ways. The most obvious, of course, is that they are produced in the spoken mode. This difference also entails less opportunity for planning what you are going to say, and no possibility of editing or revision. A speaker can say something again in speech, but he cannot erase the original utterance.
In addition, there are differences in the typical communicative functions of many spoken registers when compared to written registers. Many previous studies in linguistics have focused on the ideational function of language: how speakers use language to communicate ideas and information. Language is intimately connected to ideational functions: it is nearly impossible to communicate a new idea without using language. Ideational functions are also important for the description of registers. For example, in Chapter 5 we show how many written registers have the primary purpose of communicating new information.
However, in everyday speech, speakers are often more concerned about conveying their own feelings and attitudes than describing or explaining factual information. In addition, spoken registers are usually interactive; most of the time when we talk, we are using language to communicate with a specific person – the interlocutor – who responds directly to us. In this case, we use language to support and develop the relationship with our interlocutor. These uses of language – the interpersonal functions – are fundamentally important in most spoken registers.