During the Pentecost, the apostles spoke in tongues understood by people of many languages. It's actual human languages which others people understood and it's backed by the fact that it's not the rambling most people do today all in the name of speaking in tongues.
In my opinion, I would say that if the speaking in tongues lacks interpretation, clarity, and love, it's just a rambling of nonsense. Paul in 1 Cor. 13:1 have the same assessment on the same subject.
How can one tell if a particular speaking in tongue is real or fake?
By the peace of God in your spirit.
I've heard plenty of tongues on youtube videos. I remember Sid Roth speaking in tongues...and, either it was fake or the Holy Spirit has one heck of a sense of humor!
You asked a good question, because people don't believe in hardly anything nowadays, even Christians!
I'll tell you how speaking in tongues happened to me. I had heard about it and heard it preached on and so forth, and it was sriptural so I wanted it and had never spoken in tongues before.
Now the way I learned it, is that it is the Holy Spirit speaking throgh us praying to God for us, because we don't know how to pray effectively anyway. I voiced my interest on a forum or two and a couple times IRL to people. I got as many different answers about it as there are flavors of pop. A couple people actually suggested that, they could teach me how to speak in tongues...and that didn't sit right with me. Because if tongues is the Holy Spirit praying for me...who am I to put words into His mouth?! I can not speak for the Holy Spirit on demand!
So I prayed about it and talked about it, and read about it, and listened to it and it went on and on, with no good answers. Then one day I was sitting at my desk thing and not even thinking about tongues. I was preparing to pray about something. I forget what, but as I began to speak in prayer, I spoke but the words that came out were in tongues! Not by me in the least!
Now i'm pretty quick on the uptake so I knew immediately what was going on, so I stood down in my mind and did not speak of mine own, until after He was finished. I guess it was about 5 or 8 minutes? Not long and when the Holy Spirit stopped, then I prayed my feeble prayer, lol.
So I spoke in tongues, but I didn't try to. It just happened. It didn't happen again for quite a while. and that didn't bother me, for I now know, I do not put words in His mouth, He puts words in mine! Until one morning when I woke up speaking in tongues. And that started happening as I was waking up quite a bit, and that wasn't me either! It still happens sometimes. Always early in the morning as I wake up, I'm already speaking!
It sounds Twilight Zone, but that's what happened. so Tongues is real and it is a thing to be desired according to scripture, so I'm at peace about it now. And if it happens, I praise God and keep on trucking!
It also seems like, when I hear tongues on a video, I can get a feel for it if it is real or not. I've never been able to (be given) interpretation of tongues, but that's ok, I trust the Lord.