Other familiar cat sounds are the aggressive hisses and growls, the howls of females in heat, the chirp and chatter of hunting cats and the famous purr. The Purina Encyclopedia of Cat Care notes that meows are directed almost exclusively at humans. The pitch of the meow can help you understand its meaning. If the sound is high toned, than the cat is probably quite happy to convey his message. A welcome meow is usually quite high pitched.
Cats have a wide collection of sounds other than the meow.
Hisses, growls and screams, chirps and chatters, and of course the famous purr are familiar feline vocalizations. Hisses, growls and screams are frightening sounds usually made by a scared cat. The cat feels threatened and wants to discourage the perceived foe from attacking by using intimidating body posture and vocalization. These are very strong words in feline talk. Chirps and chatters can sometimes be heard when a cat looks at potential prey without being able to reach it.