I went to a Pentecostal church gathering as part of my exploration of religions and there was a point at which several members began to babble in so-called, Tongues. It was as embarrassing as all hell to see this up close, to see what fools people will make of themselves to remain part of the tribe. I asked a Pent. minister who was close by, what are they saying and why are they speaking in Tongues.
He told me it was a lost, ancient language and they spoke in Tongues to confused the devil. He then said, we now have to wait for somebody else to interpret it back into English. I then said to him, I guess the devil doesn't understand English either, at which point he moved away from me.
Tongues is a form of communicable delusion, but it likely produces a mild ecstasy not dissimilar to the effect of Whirling Dervish movements, the ecstatic dancing of Voodoo, the quaking of the Quakers, the singing and dancing in the black churches, the drugs and drum beats in indigenous religions. It likely sets up a mild state of euphoria.
Tongues is harmless enough so long as you don't take it too seriously, it's not an ancient language, it's not any kind of real language, it's human, creative imagination at its best and when a member warbles this utter nonsense it welcomes them into the deeper fellowship of superstition and dogma that is the bedrock of most religions.
Nothing to be scared of, it's just religious humans doing what they always have, making shite up.