President Joseph Smith taught, "As to the gift of tongues, all we can say is, that in this place, we have received it as the ancients did: we wish you, however, to be careful lest in this you be deceived. . . . Satan will no doubt trouble you about the gift of tongues, unless you are careful; you cannot watch him too closely, nor pray too much. (History of the Church, 1:369)" The Prophet goes on to state the purpose for the Gift of Tongues as, "given for the purpose of preaching among those whose language is not understood. (History of the Church 3:379)" However, the Prophet Joseph gives this warning, "Be not so curious about tongues, do not speak in tongues except there be an interpreter present; the ultimate design of tongues is to speak to foreigners, and if persons are very anxious to display their intelligence, let them speak to such in their own tongues. The gifts of God are all useful in their place, but when they are applied to that which God does not intend, they prove an injury, a snare and a curse instead of a blessing. (History of the Church 5:31-32)"
To put in simply, when a person preaches the Gospel of Jesus Christ in a different language than their own, they are using the Gift of Tongues. There is, however, a false manifestation of this gift we must be wary of.
False Manifestations of the Gift of Tongues
President Joseph Smith also taught, "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. (History of the Church 4:580)" Lastly, the Prophet says, "If you have a matter to reveal, let it be in your own tongue; do not indulge too much in the exercise of the gift of tongues, or the devil will take advantage of the innocent and unwary. You may speak in tongues for your own comfort, but I lay this down for a rule, that if anything is taught by the gift of tongues, it is not to be received for doctrine. (History of the Church 4:607)" Thus those called "Holy Rollers" are left in the dark, because their version of the Gift of Tongues is a false variation, so saith the Prophet Joseph.
I know that The Church of Jesus Christ of Latter-day Saints is true, and that it is the only Church to correctly teach the Gift of Tongues and interpretation of tongues. I know Joseph Smith was a prophet and that Jesus Christ is the Savior of the world. In the name of Jesus Christ, amen.