My first encounter of speaking in tongues was when someone I knew was in the psychiatric ward of a hospital in Scotland.
They telephoned me on a regular basis for prayer and whilst there met a woman who was a believer and had been battling mental illness for years. She did not understand why having had no episodes which required hospitalisation for some years God would let her return. But having met the person I knew she knew why this time. The lady whilst talking to me whom I knew nothing about till that phone call asked could she pray for us. It was then she started praying in tongues and in that instant I knew all about her and what God wanted her to know. When she had finished I told her everything and she started to cry with relief.
Everything I had told her was completely correct and what she had been waiting for God to answer.
So both she and the person in hospital with her received what they needed.

I have never been aware of speaking in tongues whilst awake and I am not a person to fake anything or pretend.
I do not believe in pretending to make noises and calling it tongues.
However, one night I had been talking with God before I must have fell asleep (don't remember doing)about this very matter of speaking in tongues. I was before God and we were talking about what was on my heart and as I awoke I was speaking a strange language and God was calling me by a different name. A name I would have when I was with him. But as I awoke speaking in that strange tongue he told me I would not remember the name because it was for then and not for this life.

When I awoke the name was gone and the language I was speaking I could not do it.

I have had no problem with not speaking in tongues since. But I have had the experience of knowing the things on someone elses heart when they prayed in tongues for me. I had seen that and I had experienced the above.

Speaking in tongues is for Believers not for the World.