Posting here because, for some reason, I can't post in any DIRs.
I spent time with a Pentecostal denomination but didn't convert to it. One thing I walked away with was the impression that, regardless of their scriptural arguments for speaking in tongues (which are adequate), the practice is fake.
Speaking in tongues, as they practice it, is supposed to be speaking in the language of angels. However, there is no grammatical structure. Most of the words are collections of random syllables. The one time I did feel compelled to speak in tongues, I stopped just short of it, as I realized that the words in my head were just random Middle Eastern city names and words I knew. The pastor who was always (like, once a month) running off to Africa on missions happened to have very African-sounding words (but still not actual African). The girl who was studying French had French-sounding words.
The Pentecostal justification for it is that the words do change to suit you individually. Then that's not a language of angels. It's obvious bull****, teased out of people through showy services that are meant to excite and pressure the audience.
Speaking in tongues is an interesting experience. Speaking, kind of sentences, gibberish, hearing this come out of yourself without any conscious thought or control behind it. Because there is no conscious control, I can see where folks would feel this as supernaturally inspired.
It's, IMO, something the mind can do. Letting the subconscious assume control of speaking. You're not in control of it, it must come from somewhere right?
Consciousness has a very limited awareness of what happening with the Central Nervous System. The subconscious mind is faster and much larger really much more aware then our conscious awareness. It has a lot more physical control of the body than the consciousness. It's just we are completely unaware of it, so it seems like the conscious mind is in charge.
We identify ourselves as the physical body. This is who we see ourselves to be. I think the reality though is our conscious self is more like a pimple riding around on the butt of the physical body.