Yes, that noisome babbling the Pentecostals do that they so delicately refer to as "prophetic utterances" are a key part of their religion. Though from what I've heard, a lot of them do that stuff not because they think they're filled with the holy spirit, so much as they want to fit in with all the babblers around them.
While prophetic utterances seem to be a part of most religions, it seems to play a key part in the religion of Pentecostalism. I do not follow any type of religion, but I always found it puzzling how believers can continue believing prophecies that do not come true. I think that faith sometimes is just something people need.
Yes, this is supposed to be the spirit of the lord coming out through them, as they beleive. I think that it is all fake, but a whole lot of them think that this is real, and it is a very important part of their religion and to their faith.
I'm an atheist, but for one year I made it my purpose to go to religious gatherings, ceremonies, and whatnot. And I mean every faith. Pentecostalism does tend to use prophetic utterances more often than the other sects of Christianity. Even more than the Roman Catholics, who have beautiful ceremonies.
I do not believe prophetic utterances are a key part of Pentecostalism. I believe they do have a belief of speaking in tongues so to speak but these utterances are sometimes not reconcilable with prophetic utterances. I don't believe these two ideas are exactly the same so it's unfair to attribute the suggested acts.