It is a simple principle - invite many into leadership training. I'm not encouraging you to prematurely invite them into a formal leadership position. On the other hand, by putting a basic leadership training class in place you will have something to invite budding leaders to. Spiritual leadership is imparted through communication gifts. In each of Paul's listing of leadership job descriptions he mentions the ability to teach.
Teaching is one part acquired skill, one part gifting, and one part simple patience.
When Paul says leaders need to be able to communicate he isn't saying that they must be budding public speakers. I don't think he was calling each of us to hit the road ala Billy Graham. Be available to answer their questions. The kinds of leaders you are looking for are the kinds who can answer questions - both those outsiders ask, and the ones that our teams ask. There is a difference between loving outsiders and simply tolerating them.