A discourse is a way of speaking that emerges within a certain social setting and is based on a certain subject matter. A particular discourse becomes a language variety when it is used in this way for a particular purpose, and is referred to as a register.[24] There may be certain lexical additions (new words) that are brought into play because of the expertise of the community of people within a certain domain of specialisation. Registers and discourses therefore differentiate themselves through the use of vocabulary, and at times through the use of style too. People in the medical fraternity, for example, may use some medical terminology in their communication that is specialised to the field of medicine. This is often referred to as being part of the "medical discourse", and so on.