(30-03-2019, 07:34 PM)MarcoP wrote: You are not allowed to view links. Register or Login to view.Than there is "glossolalia", which has been recently mentioned by Geoffrey. The phenomenon apparently exists since ancient times, though I don't think there are ancient written examples.Emphasis mine.
I don't believe that's really a given and can only state that I would be very cautious about this.
This thread is probably not the best place to discuss such a matter but it might be worth a thread in the "non-voynich medievalia" subforum to present and discuss the supposed evidence for this. In my understanding, the biblical passage described by Markus in You are not allowed to view links. Register or Login to view. thread is ambiguous at best, the Catholic Church only dedcided to embrace such claims by charismatic movements in the 20th century and, as I stated in that thread, the glossollalia terminology was given the meaning that we understand today during the 20th century.
As MarcoP states, there are (to my knowledge) no prior written examples of glossolalia, nor is there any reason that would lead me to believe that any christian religious subcultures existed in the middle ages that practiced speaking in tongues in the sense that we attribute to it today.
ETA: I broadly agree with Koen G's concluding statements in the OP.