The first skill of speaking out the front is…

…learning how to NOT speak, and being comfortable with the silence.
Whether you’re training MCs, band leaders, prayers or preachers, if they’re not able to cope with not-speaking, they’re going to try and fill all the gaps. And when you’re trying to fill gaps, you’re not thinking about what you’re saying, you’re just thinking, “ahh, I need to fill this gap!!” And that’s when you do one of two things; either you speak for too long about nothing things and bore people (imagine the band leader who starts their song intro, but doesn’t quite stop). Or you say something silly, wrong, hurtful or heretical.
The solution is silence.
Tell your band leaders, “This week, show me that you can NOT speak, and then we’ll move onto speaking next week.”