Krishna was eating mud and Yashoda was furious to see this! She ran to Krishna and in an attempt to remove mud from his mouth, ordered Krishna to open the mouth. When Krishna opened his mouth, Yashoda saw the whole universe inside his mouth; earth, sun, moon, planets, hell, heaven everything! Seeing this Yashoda fainted!
Every mythology stories has something to teach – deeper and subtle. Krishna wanted to express the importance of using positive vocabulary because it has impact on what you experience in the world. If you speak good things, keep negative words out, be pleasing to people, then world will reciprocate and you will experience a world that is happier. Possibilities will be more. Freedom will be more.