A meow/miˈaʊ/, also spelled miaow, is the most familiar vocalization of cats. A meow can be assertive, plaintive, friendly, bold, welcoming, attention soliciting, demanding, or complaining. It can even be silent, where the cat opens its mouth but does not vocalize. Adult cats do not meow to each other, and so adult meowing to human beings is likely to be a post-domestication extension of mewing by kittens.