Dangerous stuff and open to fraud.
I know a fellow who was in a evangelical revival and the preacher preached on the necessity of tongues to be a Christian. When it came time for prayers some prayed in tongues and an interpreter then translated their tongues into English.
So, the person telling me this story stood and prayed the Lord's Prayer in Greek. The interpreter interpreted .... but completely wrong. The interpretation had nothing to do with the Lord's Prayer or with prayer at all.
When I was a kid there was a woman in my neighborhood ... in the country ... who spoke in tongues at every service in her church. She was second meanest woman I knew, very vile, very foul mouthed, etc.
The meanest woman I knew got away with murder. Literally got away with murder. The pigs ate the evidence.
It bothered me as an adult that when I was at a local charismatic church and charismatic conferences that speaking in tongues were turned on and off by the leaders. A "Let us pray" and just about everyone began speaking in tongues. After a few minutes the preacher or the prayer leader would raise his hands, make a motion and everyone would cease speaking in tongues. I don't believe the Holy Spirit can be turned on and off at will. [Just my belief.]
So, as a kid I was never impressed by those advocating tongues. I still am not. No offense meant here, just relating incidences from my life.
When I was in college, I met a couple of Hebrew students from California. They told me they had gone to a pentecostal prayer meeting where some would speak in "tongues" and then others would give an interpretation. One of these hebrew students stood up and merely quoted Psalm 23 in Hebrew. Up stood a supposed interpreter with the gift of interpretation and gave some long outlandish interpretation about the Lord's return.
I have personally attended various Pentecostal denominations during their tongue speaking. Indeed, in a small city not too far from my present location I attended a youth rally when everyone in the building except me alone broke out into what they called "tongues." Mass confusion, no interpretation given at all, the word of God trodden underneath their feet and yet they had the audacity to claim the Holy Spirit was the author of such confusion (1 Cor. 14:33).