Murmurs Include Purring
Murmurs include purring and the soft, happy chirp of greeting. The source of the cat's purr remains a mystery. However it is done, it is not always a sign of happiness.
Stressed or traumatized cats also purrr, a phenomenon familiar to vets who treat injured or ill cats. The chirp, like the purr, does not involve vowels. It sounds like a "brrrp" or "brrrm," and is uniquely used to show pleasure.
Vowels, the classic "meows," vary according to what is meant. Domestic cats talk with meows because we have extended their kittenhood.
Requests, demands, commands, complaints, and bewilderment have subtle variations that are easy to understand, and with which owners become familiar.
High-intensity sounds are natural adult cat language, and as such they are usually reserved for communicating with other cats, although some are familiar to owners and veterinarians.
Changing the shape of the mouth creates many sounds, from a grumbling, irritated growl to a threatening snarl, a hiss, or a defensive spit. Shrieks of fear or pain and the wail of females in heat are made in the same way.