I know lots of people who are scared of public speaking. Our church has kids beginning to bear testimonies from toddler size. New members are usually hesitant to speak, but we have so few people in our congregation, it's like just talking to close friends. But even then, many folks are not happy to give a talk!
We don't have a preacher or a reverend as such; the sermons are given by members from the congregation, assigned a week or two ahead so as to prepare. Many use talks by the Elders or the Prophet and mostly read the talks. But many incorporate personal stories that inspire, too. It isn't done in a set order (every 15th Sunday?) but when the Bishop or his counselors ask you. We get right down jiggy when people visit and bear their testimony, or have a talk assigned; it's fun to hear new speakers!