Up on your understanding of dicsourse structure, I would like to share your ideas about the minimal structure of a discourse. Discourse analyists suggest and recommend that for discourse analysis the structure of discourse should not be less than two sentences. However, in the discourse of everyday communication sometimes we encounter the use of sign language or facial expressions and body movements. More particularly, in some places and institutions such as post offices or airports we usually find posters and wall signs telling us not to smoke or lead us to mens' and womens' toilets. The question here is that can we consider these signs and posters to be discourse or not. Thanking you for exhanging your views and comments.