Your cat may speak a different language than your cat but you can still communicate with each other. Cats are often alone and can go for long periods of time without interaction but they will use body language when they want to communicate with you.
When your cat is very happy they will do something called kneading, the cat works her paws on a soft surface as if it she’s kneading bread dough. It’s a holdover from kitten hood, when a nursing kitten massaged her mother’s teats to make milk flow.
You might be standing in the kitchen and they are rubbing against your legs or rubbing against a piece of furniture, he is marking his territory. It’s your cat’s way of telling everyone around that this is his territory, including you.
That pretty purr you hear from them is normally a sign of contentment. Sometimes it may be purring when he is sick, but mostly they are happy when purring.
Unlike a dog, when a cat is wagging his tail it is not a sign of happiness. A cat is agitated when thrashing his tail back and forth, and the faster it goes the angrier he is.
So how do you know if he wants attention or be left alone? If your cat arches his back while you are petting him, keep on going he is enjoying it. If he shrinks away when you touch him, leave him alone and try again later.