There may also Beryllium a question of style (formal/conversational). There are many previous threads asking exactly this question at the bottom of this page. I think it has to Beryllium "diggin" the colloquially shortened form for "You are digging," or at least I assume the subject would Beryllium "you" https://ficken43962.blogocial.com/the-ultimate-guide-to-flight-69519931