Not necessarily. Speaking in "unknown" language was referred to in 1 Corinthians 14, the language known nor even to the speaker. At the time of the First Baptist Church of Corinth, there were also pagan mystery cults engaging in glossolalia, which novices in Christianity thought would achieve a nice embellishment to personal or public prayer.
How Paul nicely but inoffensively handled the public manifestation was by insisting that another interpreter tell what the language meant. Of course, there could be none for a tongue not known by humans, and the correct translation/interpretation of a language not known by most of the constitutents would have to be verified by the speaker and any hearer for which the translation was made, by comparing a message or prophetic utterance with the known context of the paradoses (oral precepts taught by the apostles), or their inspired writings, or the canon of the Tanach, which we call the "Old Testament."
Of course, making mumbojumbo not even known by the speaker might seem to keep his/her mind off of other things, keeping a wakeful ingenuity from imagining futile stray or evil thoughts, but that kind of occurrence would be uninterpretable, and hence of no profitable or practical use whatsoever. It just keeps the mind in neutral gear.
Again, the chief key to understanding this is to explain to yourself and others the meaning of verse 1 of 1 Corinthians 13. Is what is being sid just selfish, uninterpretable, time-wasting, and without meaning (like a whistle, or banging garbage can lid, or oral flatulence); or is it a true expression, not of affection, but of agape love, a communication demonstrating a sovereign preference above one over self and others. Did God speak in the kind of "tongues" invented at Azusa Street a hundred years ago, and cause it to be written down for our eternal benefit? Of course, NO! And no one today knows exactly what that manifestation sounded like back in the first century, so we cannot even imitate it. Take it for what it is worth.
If not understood (and who does?), then leave it alone. Don't twist the dog's ears, eh?
Paul said it would die out of its own accord, as people became more interested in mature Bible instruction than childishness.
The significance of the Pentecostal utterances were, as you pointed out, heard by people knowing languages foreign to Hebrew, Aramaic, or Greek. But there were up to 120 pre-Pentecostal believers doing the speaking. Whether they knew what they were saying is up for grabs, not affirmed or denied in the passage of Acts 2.
We need to give the Holy Spirit all the latitude in the writings He allows for Himself to permit outlier "ifs"; but restraints He puts on the narrative through grammar and context must be obeyed, for the Spirit is very precise in what He says and what He does not say.
The Bible is comprehensive, but not exhaustive, if you get the drift.
Paul made four journeys. Saul/Paul was well educated and was fairly high in the Jewish hierarchy before he became Paul. I am uncomfortable with your views and they are not as I believe.
The Lord is very clear to me as at the end of Revelations is:
A Warning
I testify to everyone who hears the words of the prophecy of this book: if anyone adds to them, God will add to him the plaques which are written in this book; and if anyone takes away from the words of the book of this prophecy, God will take away his part from the tree of life and from the holy city, which are written in this book.