Effective communicators know words are only a part of what makes them successful. Voice inflection, facial movements, body language, word choice, and, most importantly, how they handle unexpected situations, all contribute to making a skilled communicator. Additionally, reading these expressions and listening not just to the words of a speaker but the overall way he or she speaks can give the listener some pretty powerful information. Is the speaker holding something back? Lying? Is he or she selling something too enthusiastically? Will they lose their temper? Will they be honest? Knowing the principles of persuasion and how to read others will give you an advantage in every business situation.