This document discusses the differences between communication and public speaking. Public speaking is a formal act of communication where an identified speaker presents a message to multiple listeners to achieve a purpose. It describes the communication process as transactional, with a sender encoding a message through a channel to receivers who decode the message. It notes potential problems like noise interference and issues in translating between languages. Effective public speaking requires building rapport with the audience and understanding that all communication, whether intentional or not, is continuous, irreversible and unrepeatable.