
What is wrong with "the Spirit talking to Himself."  Jesus intercedes
for us, and Romans 8:26-27 tell of how the Spirit intercedes for
us before God.  That is no theological problem.  Tounges as a prayer
language finds support in I Corinthians 14:14-18.



Its true that this could be (and has been) used as a rug to sweep
any difficulties under.  But it is a valid point.  Paul does mention
angelic tounges in the verse. 



If the languages we sepak are the result of Babel, then it stands to
reason that angels would speak a different language from us.  You do 
have a valid point about multiple angelic languages.  But angelic
beings maybe of different species so to speak.  maybe different species
communicate differently.  


I have heard an eyewitness account, myself.  Such things are hard to prove.
They don't lend themselves to a laboratory thing very well.  I don';t
know if it is a very holy thing to take gifts into a laboratory anyway.


That's an unprovable statement.  How can you prove if somethings been proved?
There is no way to know that you've seen all the evidence.  Once I 
saw an orthodontists records complete with photographs showing how one of
his patients severe underbite was cured by constant prayer.  

John G. Lakes once prayed for someone and saw them healed in a laboratory,
according to "Adventures in God."  Its an interesting book.