Cats purr to communicate contentment when we pet them. They also purr when they are afraid or sick. Their purring helps to calm them and may have healing properties. Cats purr when approaching another cat in a friendly way, trying to make friends. Other reasons that cats purr for self-comfort when they are afraid, sick, or in some kind of distress, so purring is not always an indication that all is well.
Among other diverse sounds that cats make are meowing and
chattering. Many cats meow at you for food and for attention. Many
Siamese will “talk” to you more than you might like. A few of my cats
also do a great deal of chattering, especially when they are excited
about seeing those critters and birds while doing some kitty window
shopping in the living room. Chattering is a behavior that cats have in
the wild that imitates the sounds that their prey make. These sounds
can be used to trick the prey into being caught.
Best wishes for a great day for you and your cat!