You speak, write a letter, make a telephone call. Your words carry a message. People communicate with words. Do you think you can communicate without words? A smile on your face shows you are happy or friendly. Tears in your eyes tell others that you are sad. When you raise your hand in class, the teacher knows you want to say something or ask questions. You shake your head, and people know you are saying "No". You nod and people know you are saying "Yes". Other things can also carry messages. For example, a sign at the bus stop helps you to know which bus to take. A sign on the wall of your school helps you to find the library. Signs on doors tell you where to go in or out. Have you ever noticed that there are a lot of signs around you and that you receive messages from them all the time?