On split tongues... The reason people have this done will vary greatly. Many cite increased sensation, enhancement when kissing for the giver and receiver or novelty, but the reasons can be deeper as well. Challenging oneself, rites of passage, connecting with or being in control of one's body, making a spiritual connection and testing the body's limits are also reasons given. Like all body modifications, it can be used to connect or identify with a specific group or to ward off those who would make quick undesired judgments based on appearance.