As to Holly Rollers speaking in Tongues and other such acts it is hard to tell. But some studies done years back would suggest many really believe they are being possessed by God. But the Tongues part is something found in other religions beside Christianity, such as in some African and South American spiritual groups. It is an interesting study if you are curious. It was some 20 years ago when I read some in that area.

I believe they do, as much as is possible without actual objective facts. In my Bible College days and later as a Minister I would say I believed as much as possible. But at some point ZI left the ministry for personal and family reasons but continued as a faithful believer. But that lasted only a few yeasrs befor l wandered off. A few years of wandering I came back with some serious questions. I set out on some personal study of theological problems posed in a book by a well known conservative author at the time,1990. I studied with an open mind, getting out my Greek and Hebrew texts, and in the end I did not see the answers in the way the author did. It eventually led to my denying the Bible as the Word of God literally. I went through several phases of sesrching and tesdting other religious and Spiritual ways both Christapian and non Christian. And finally around 2003 I declared myself an Agnostic. Studying and understanding helps when dealing with Christians and Spiritualists. It is not necessary but like all knowledge and experience it helps to understand those we disagree with. I have walked in the shoes of the True Fundamentalidt Baptist type religion. I also walked in the shoes of the far right in the mid 70s to late 80s. I have read many of the books by the John Birch Siciety, which was the far right in my day. They would be of the Ayn Rand philosophy, which is the prevalent view of the far right today.
As the old indian saying goes, don't judge until you have walked in the others moccasins for a few miles. Loose translation. Basicly the same as some old theologian/philospher said. I think it was Kant, but not sure.