I'm not a stranger to neuro science but it is not the Holy Spirit. there is actually no way it can be proven that 'tongues' are not a language that is structured in a way different from our modern languages. when you say 'the only possible way' it is a human understanding and reasonably so.
however, God is not limited by human understanding and who knows or who can say what those tongues are other than that the Spirit of God gives utterance...to use a direct quote from scripture
can we prove God exists? has anyone proven beyond any doubt that God exists or do we believe and are saved through faith in what we have heard? I think you know the answer to that one.
it is all by faith...as Hebrews tells us. Abraham was an idol worshiper as far as we can tell and yet believed when God revealed Himself
I have had God reveal Himself and I know He is real...have I seen Him? no...no one has seen God. but He has revealed Himself through the senses He created in us human beings...I have felt His presence, I have literally heard audible singing as though a heavenly choir, I have had some extraordinary things happen with answer to prayer. I pray in tongues...I basically understand what the prayer is about...but not always but sometimes I see it down the road
that is really all we have. God is Spirit...not one of many...but the only One and He has revealed Himself to those who seek after Him
we don't walk by scientific experiments or what we see...according to scripture we walk according to what we have not seen and Jesus says we are blessed for so doing!
I could not say what is or is not an angelic language...but I do know I do not always seem to be praying the same language..
the Bible does not directly call tongues a private prayer language. Paul instructs the use of tongues in prayer when he states he will pray with both his own understanding and with his spirit...meaning his spirit praying by the Holy Spirit. people here who pray in tongues know what I am explaining
if you read I Corinthians you will find what I am talking about
and I have read and or heard all the objections with regards to praying in the spirit being something other than what I just stated
as I have said quite a few times in this forum, I grew up with the teaching that tongues should be avoided at all costs but here I am anyway