A communication system actively monitors a conversation between users in an environment. Once a threshold condition occurs (e.g., client device within a threshold distance of a room where the conversation is occurring, the user enters a chatroom via the client device), the client device receives a summary from the communication system. The communication system may customize the summary in accordance with user preferences. User preferences may include level of detail in summary or time range associated with summary. The client device then presents the summary to the user. The summary may be audio or text. In some embodiments, the summary may be historical audio that is overlaid over current audio at faster speed and higher volume, and stops once the historical audio reaches real time.