Cats have many different expressions. When they get up from a nap, they yawn. Occasionally you will catch your cat sticking out his tongue while stretching. When they are excited, their pupils grow larger and wider. When they feel contented, they keep their eyes half opened as if they are falling asleep.
Cats know how to communicate with their body. They are aware that people do not always get their body gestures, so if they want something, they often incorporate their vocal skills to get what they want from us.