Why is it so hard for you to understand? You said no one knows what the tongues in the Bible times sounded like. Then what do you think nowadays tongues are? Are you admitting they are fake?
So even if the biblical speaking in tongues did not sound like any earthly language, (as many nowadays tongue speakers claim it is not an earthly language), speaking in tongues was still heard and understood as different earthly foreign languages....by the foreigners themselves (see Acts 2:6 and 2:11).
I do not think that nowadays tongue speakers are mad, because I know what they think they are doing.
You should not confuse Acts 2 with what Paul is talking about in the Corinthian letter. They are not the same.
Think about it, rather than being reactionary. In Acts two, is there any hint of the need for interpreters? No. Each man (as in "every" man) heard what was being preached in their own language. Did anyone think the Apostles were mad men, talking in tongues without an interpreter? No. What was edified, the mind or the spirit? The mind.
All of these considerations, have an opposite answer to them, if reading the Corinthian discussion of tongues.
Look, I used to believe exactly as you do. I ministered in Churches of Christ for 14 years, before leaving that fellowship. I worship with a very open minded, loving, Baptist church, now (and there are many such churches that do not fit this "loving" description). During my sojourn, after leaving the C of C . I worshiped with "charismatic" churches for ten years, and married my tongue speaking wife (didn't know she had this gift, at the time). I am ashamed to say that I preached the very things you believe, believing I was right.
I have attended many services in which tongues were featured, and, in those churches, the problems they have with with tongues are the very same problems the Corinthian church had. If the problems are the same, if Paul's comments and cautions work in the Charismatic Churches of today, why should any of conclude that the actual "tongues" event is different.
I still do not know what that first century experience was like, but I know the Pauline cautions work for all of "charismata," I know of these people's faith (keep in mind that I, myself, am not a tongues speaker) is as deeply felt as mine, they are as committed to the Lord as I am, if not more, and God blesses them in the very same way as he blesses me, in my Baptist-English speaking church. We serve the same Lord. And, since we are saved IN SPITE of ourselves, you included, all of us should be able to share in the fact that we are all prodigal sons of the Father.