It is important for leaders to know the various leadership languages so that they can have personal authority. It is not enough for a leader to have a position that gives them official power. Instead, they need to have personal authority that makes their subordinates trust them, believe in them, and want to follow them.
Leaders have only one main tool that they can use to get people to do what they want. That tool is the language they use. Leaders therefore need to know a variety of leadership languages. They need to know a language that shows others that they can listen and learn in a variety of situations. They need to know a language that demonstrates that they have ideas that are worth following. They need to know a language that shows people that the leader cares about them. If a leader can only speak one or two of these languages, they will be incomplete. They will not be able to get people to follow them in a broad variety of circumstances.