If this behavior is new, you should talk to your vet to make sure there’s nothing medically wrong with your cat. Your cat may be in distress or suffering from a medical issue. If your vet has confirmed there’s nothing wrong with your cat, resist the urge to give them attention when they’re meowing. Instead, wait for them to stop, and then shower them with attention. If you're consistent, they’ll catch on and associate being quiet with getting lots of love and attention.