Field of discourse is one of the social variables that determine the register. Field of discourse refers to what is going on: to the area of operation of the language activity. It is concerned with the purpose and subject matter of communication. It answers the questions of “why” and “about what” communication takes place. Field of discourse may be non-technical or technical: shopping, game playing, and a personal letter are instances of nontechnical fields. Technical fields refer to the specialized fields such as a linguist giving a lecture in class and meteorologists talking about the weather. The field of a register determines to a great extent the vocabulary to be used in communication and it also determines the phonological and grammatical features of the language.