In a lot of ways, when you step out to talk to a group of people, you do become larger than life. That is because you are doing the impossible. You are having a conversation with dozens of people all at once.
Now, whether you feel like you are having that conversation or not isn't important. What you are saying is getting down inside of them & they are reacting to it. But even more than what you are saying, how you are saying it is having an even bigger impact. So are there things you can do to "become" larger than life?
Well, there are some ways of behaving in front of a crowd that differ from daily life. We do have to accept that you will develop a "stage persona" that is different from your daily personality when you speak to a group. Does that make you a phony? No. Both of those personalities are you. It is just a different you when you relate to a group than to people one on one & it seems strange because that form of you only comes out on stage.
Just as you speak to a child differently than you speak to an adult, you will develop a way to talking to a group that differs from speaking to an individual. It can be a bit strange if you watch yourself become larger than life. Enjoy it and let others enjoy it too.