Thank you for sharing.
I did not do the research, however, Joseph Smith had reported such false tongues among the assembly.
Mormon Q and A: Do Mormons Speak in Tongues
"We have also had brethren and sisters who have had the gift of tongues falsely; they would speak in a muttering, unnatural voice, and their bodies be distorted … ; whereas, there is nothing unnatural in the Spirit of God. (See History of the Church, 4:580; punctuation modernized; from “Try the Spirits,” an editorial published in Times and Seasons, Apr. 1, 1842, p. 747; Joseph Smith was the editor of the periodical.)"
"Speak not in the gift of tongues without understanding it, or without interpretation. The devil can speak in tongues; the adversary will come with his work; he can tempt all classes; can speak in English or Dutch. Let no one speak in tongues unless he interpret, except by the consent of the one who is placed to preside; then he may discern or interpret, or another may. (See History of the Church, 3:392; from a discourse given by Joseph Smith about July 1839 in Commerce, Illinois; reported by Willard Richards.)"
Although instructed, it stands to reason why that researcher found what he did because not all Mormons heeded such instructions.
However, I am of the mindset that because Joseph Smith did prophesy falsely and Mormonism does come off as another gospel, I am less incline to believe they actually had the gift of tongues with interpretation because Joseph Smith nor the church was reproved of what is not of Him.
Same with the Charismatic Catholic Church. It just doesn't align with what the indwelling Holy Spirit would not have left undone.
I have heard the report like this guy, but he did say the " "Spirit" so strong in that room " which is testifying to the presence in the room rather than in himself ( 1 John 4:1-6 ) which by this test is the spirit of the antichrist, and the fact that he is bearing witness of himself cannot be considered a true witness but a false witness. ( John 5:31 & John 7:18 )
I have heard of a church that has thought they had God's gift of tongues as it was being interpreted; then they hired a linguist to tape it all and translate it, but it all came back as gibberish nonsense. Joyce Meyers said how she interpret tongues is by getting the feel or the gist of what is being said is how she interprets tongues. It is no wonder why that other church thought they had the gift of tongues if members in there had thought as Joyce Meyers had thought on how to interpret tongues.
Now Joseph Smith may have spoken some truths about speaking in tongues and have given instructions for its use, but that doesn't necessarily mean all Mormons followed it, let alone make sure that they were speaking in tongues and not winging the interpretation either. It probably why even Joseph Smith had caught some using what he says is "fake tongues".
At any rate, no one should be swooning over any person or church claiming to speak in tongues when the focus and the spotlight should be on preaching Jesus Christ and Him crucified and nothing else in His name for why we are all to prove all things & abstain from all appearances of evil.