justbyfaithwrote,
I don't know if this has been mentioned; but 1 Corinthians 13:1-3 tells us about a heavenly language that is not known to men...tongues of angels.
This doctrine only became popular after missionaries went into the field and tested their newly-acquired gift of tongues in China, Japan and India. It was an abysmal failure; none of the natives understood a thing they said.
Charles Fox Parham, the acknowledged father of the modern tongues movement, believed (rightly) that tongues were actual languages, not some angelic language. It was only after the epic failure of his missionaries that they recalibrated and came up with the "angelic" idea.
It's right there in I Corinthians 13:1-3. Paul wrote I Corinthians
before the Azusa Street Revival in the early 1900s. My guess is that the idea that when Paul says, 'Though I speak in the tongues of men and of angels...' A straightforward reading is that both might be possible. After all, giving all to the poor and giving one's body to be burned, parallel ideas in the passage, are possible.
I suspect someone at Azusa Street had read the passage. If Parham insisted on human languages and had the unbiblically-supported idea that tongues were for preaching the Gospel, that does not mean no one in the movement could have read or been familiar with I Corinthians 13:1 before the revival started.
At the Azusa Street Revival and other meetings at that time, there were many people who experienced their speaking in tongues being understood as a foreign language or else understanding a tongue spoke in their language. I went through a couple of editions of 'The Apostolic Faith', the newsletter for the revival and came up with many cases of someone speaking in tongues and someone else understanding the language, somewhere between 8 and 12 in two of the later editions. One testimony was of a Canadian minister who heard someone in his group speaking in tongues in a first nations language he knew where he was raised on the opposite side of Canada from where she was from. Another language was Armenian.
Several books share testimonies of these things happening from the revival at Azusa Street, The Comforter Has Come. Fire on Azusa b Val Dez tells of a case at Azusa Street with Russian. Vinson Synan's interview with two elderly people who were children at the revival discuss the topic of real languages and one of the interviewees said what made the meetings grow is when people would come in and hear tongues in their own languages, and she mentioned a few of them.
AG Garr's experience had to do with someone saying he spoke Bengali, thought it did not sound at that time, like what he usually said when he spoke in tongues. But when he went India, he didn't speak the local language in tongues.
Biblically, there was a problem with the assumption of Parham and some of the other Pentecostals who thought they would evangelize the world in tongues. Acts 2 does not even say the disciples preached the Gospel in tongues. They spoke of the wonderful works of God, then Peter stood up and preached the Gospel.
As far as I know the idea that speaking in tongues IS the tongues of angels is not the position of any Pentecostal denomination and never has been, not any I am familiar with. There are too many testimonies of the occasional case of someone understanding speaking in tongues, the missionary who comes back and hears the language from the field spoken, or the missionary who had an experience on the field. I have spoken with four people I can think of off the top of my head who have had experiences with hearing tongues in a language they knew or being told by someone that they spoke a language they knew while speaking in tongues, and I've corresponded in the online environment with others.
Paul described the situation in church meetings in Corinth... and this is the norm... one person speaks in tongues and 'no one understandeth him', so Paul encourages interpretation to edify the church.