"Skyrim" dragon shouts are a form of ancient magic that utilizes the language of dragons to create powerful effects. A specific dragon shout can be made up of three words, but vocalizing one or two words is enough to generate a diminished effect.
In the Elder Scrolls game series, the dragon shouts are also known as Thu'um and are part of the language that dragons can use at will. Humans and other humanoid creatures in "Skyrim" are able to use dragon shouts, but only after long meditation and practice. An exception to this rule are the Dragonborn, mortals who are born with the soul of a dragon.