Cats use a variety of meow types in a general, nonspecific way to attract the attention of their caretakers. It follows that additional cues such as body postures, orientation and activity level are equally important for communication. Studies suggest that cats use a variety of meows in general and again, paired with body language, they try to effectively communicate with people. Body language includes facial expressions, body, and tail positions to help express their feelings and get their message across.
Cats vocalize frequently with owners, with the "meow" noise being the most common. Purring is also a very common kitty sound, and is usually associated with pleasure or contentment- though some veterinarians report purring in sick or painful cats as well. Interestingly, the majority of pet cats use the meow almost exclusively when interacting with humans but do not typically use it when interacting with other cats.
Meows are highly variable and vary with each situation, but all signify some type of good-natured social encounter. Individual cats are known to develop an entire set of different meows for specific situations when interacting with human caretakers. They develop a myriad of meows- a meow for food, play, or cuddles- all specially made for their humans and help establish understandable communication.
Adult cats typically purr when they are in contact with a human caretaker, a familiar person, or even other cats! Another type is the trill or the "chirrup". This vocalization is commonly produced when greeting people or cats, and paired with open body language, an erect but relaxed tail in a question mark position. Now these physical and vocal cues are not true for every cat, as they all have unique personalities and quirks.
FUN FACT: The purr is one of the few vocalizations that occur with the mouth closed, and during both inhalation and exhalation, versus just exhalation like most!
A cat will generally either greet in a friendly confident manner, or not approach at all. The nose-to-nose, or the nose touch, is a way cats typically greet other familiar cats. Some cats have altered this behavior to incorporate human contact and will sniff an appendage then rub their face. Some cats roll on their back to greet their owners, a behavior normally demonstrated by female cats as an invitation to play or be petted. Felines do not engage in dominant/submissive behavior that is seen in dogs. The belly-up position is most commonly a play posture. Though we cat owners know that even though the belly floof is the softest of floofs, it typically comes with a bite or two upon contact.
Cats do vocalize with other cats when it comes to territory or personal space, and that's when the deep yowls come into play. Cats also hiss when they are fearful and/or defensive. The spit is considered to be a more intense form of the hiss, and is used to deter predators or avert threats. The howling, hissing, and spitting is usually paired up with a large sideways body posture, with the cat making themselves seem larger than their opponent. Most negative cat interactions are typically resolved through only vocalizations, but some fights can occur.
Elderly felines can become senile, and when that occurs, owners might hear them yowl at night or even during the day for no seemingly reason. Studies show that senility in cats cause deafness, confusion, and ataxia. It is uncertain why these cats meow so vociferously and frequently, but the meowing seems to be directed at no one and might exhibit new meows from their repertoire.