Universal Grammar is a theory proposing that the ability to learn grammar is embedded in the neuronal circuitry of the human brain and language learning is facilitated by a predisposition that human brains have for certain structures of language. This theory shows that linguistic ability reveals itself without being taught and that there are properties that all natural human languages share. Universal Grammar suggests that every human brain has the innate property that causes it to posit a difference between nouns and verbs whenever presented with linguistic data.