The notion of context situation

Regarding the notion of text and context, Halliday and Hasan claim that these are aspects of the same process. There is text and there are other text that accompanies it: text that is "with", namely the con-text. This notion of 'what is with the text' goes beyond what is written: it includes other non-verbal goings-on - the total environment in which a text unfolds. This total environment is the context of situation, a term which was first introduced by the anthropologist Bronislaw Malinowski. Sometimes it is impossible to understand the message unless you knew what was going on, what was happening at the time. Sometimes a message can be understood only if you know something that is in the culture or in your knowledge. The knowledge of the context of situation is crucial to understanding the meaning of verbal exchanges.
The context of situation also helps us account for the language being used. On the basis of knowledge of the context of situation, we can make predictions about what people are going to say, which makes communication easier.
In Halliday and Hasan words: we always have a good idea of what is coming next, so that we are seldom totally surprised. We may partly be surprised but the surprise will always be within the framework of something that we knew was going to happen. And this is the most important phenomenon in human communication.
The context of situation can be analysed according to three parameters:
FIELD, TENOR and MODE, which enables us to predict the language which will be used in a given situation.
The field of discourse refers to WHAT IS HAPPENING, to the nature of the social action that is taking place. To define the field we need to answer the question: 'what is it that the participants are engaged in, in which the language figures as some essential component?' The nature of the social activity comprises the kind of acts being carried out and their goals and the knowledge which is considered shared by the participants in the speech event.
The tenor of discourse refers to 'who is taking part, to the nature of the participants, their status and roles.' So we are interested in relationship among the participants, including temporary or permanent relationships, the type of speech role that the participants are taking in the dialogue and also the social relationships in which they are involved. The tenor also comprises the degree of control (or power) one participant is able to exercise over the other and the relations between participants that arise from their biographies.
The mode of discourse refers to 'what part of language is playing'. It includes the degree of process sharing, the channel (phonic or graphic) and the medium (spoken or written).