 Conversational implicatures are, roughly, things that a hearer can work out from the way something was said rather than what was said. People process conversational implicatures all of the time and are mostly unaware of it. For example, if someone asks “Could you close the door?” the hearer does not usually answer “Yes”, instead they perform the non-linguistic act of closing the door. In this case, although the speaker used a form of words that is conventionally a question, the hearer can infer that the speaker is making a request.