Some people think their cat meows at them all day because it wants their attention or because it "likes to talk". But really their cat is meowing at them because they can't speak human but want their human to know something is up.
This something could be boredom, physical pain or simply to get their owners to praise them for their great meowing skills.
However, you shouldn't disregard your cat's meowing until you know for sure there's nothing wrong with them, especially if the cat suddenly becomes way more talkative than before.
I once had a cat who kept meowing her head off until she was hoarse, and we thought she was just after our attention- turns out she had a tooth that needed to be pulled and an abcess in her gums, and had we waited any longer to take her in to the vet she might have died. Listen to your kitties, folks!