Excessive vocalization is called hypervocalization.
If you think that your cat might be hypervocalizing because of pain, take him or her to your veterinarian.
The most common reason that cats hypervocalize is that they have learned that it helps them get what they want.

Most cat owners appreciate some vocalization—meowing, purring, etc.—from their cats. The many sounds that cats make help us communicate with them by telling us what they like, dislike, want, and need. However, some cats vocalize excessively, which can become annoying to owners. Excessive vocalization is called hypervocalization.

Siamese cats and other Asian breeds known for being talkative usually can’t be trained to be quieter. Other cats hypervocalize for various reasons. Some cats hypervocalize when they’re in pain. If you think that your cat might be hypervocalizing because of pain, take him or her to your veterinarian.

The most common reason that cats hypervocalize is that they have learned that it helps them get what they want, whether it is to be let outside, fed, or petted. These hypervocalizers know that their owner will give in for some peace and quiet. Once the owner gives in, even if it takes half an hour, the cat learns that vocalizing works. The only way to reduce this type of hypervocalization is to ignore it and not reward it. You might have to wear earplugs or confine your cat to a room—whatever it takes to avoid giving in to your cat’s unwanted attention-seeking behavior. In addition, when you think that your cat is about to begin vocalizing, distract him or her with an interactive toy before the vocalizing begins. The interactive session with your cat will probably give him or her some much-needed mental and physical activity. At the end of the session, feed your cat or allow him or her to take a nap. In addition to being a distraction, interactive sessions can reduce hypervocalization caused by a lack of stimulation.

Cats may also hypervocalize as they become older and their senses decline. A common time for this type of hypervocalizing is when the house is dark at night. If your senior cat starts to hypervocalize, take him or her to your veterinarian to ensure that he or she is not in pain. If your cat hypervocalizes at night, call out to him or her to help your cat find you. It might help to confine your cat to you