New Testament glossolalia or tongues is a supernatural manifestation of the Holy Spirit (1 Cor. 12). In the book of Acts, on the day of Pentecost we read, “And suddenly there came a sound from heaven as of a rushing mighty wind, and it filled all the house where they were sitting. And there appeared unto them cloven tongues like as of fire, and it sat upon each of them. And they were all filled with the Holy Ghost, and began to speak with other tongues, as the Spirit gave them utterance” (Acts 2: 2-4). Evidently, this panorama is wholly accredited to the mystical work of the Holy Spirit. We cannot logically claim that these languages were known by the speakers because it specifically states that these believers were “filled with the Holy Ghost” and “the Spirit gave them utterance,” in which they all spoke in “other” or diverse languages. These tongues or languages spoken were understood by the witnesses of this event.
Acts 2:1 And when the day of Pentecost was fully come, they were all with one accord in one place.
2 And suddenly there came a sound from heaven as of a rushing mighty wind, and it filled all the house where they were sitting.
3 And there appeared unto them cloven tongues like as of fire, and it sat upon each of them.
4 And they were all filled with the Holy Ghost, and began to speak with other tongues, as the Spirit gave them utterance.
5 And there were dwelling at Jerusalem Jews, devout men, out of every nation under heaven.
6 Now when this was noised abroad, the multitude came together, and were confounded, because that every man heard them speak in his own language.
7 And they were all amazed and marvelled, saying one to another, Behold, are not all these which speak Galilaeans?
8 And how hear we every man in our own tongue, wherein we were born?
9 Parthians, and Medes, and Elamites, and the dwellers in Mesopotamia, and in Judaea, and Cappadocia, in Pontus, and Asia,
10 Phrygia, and Pamphylia, in Egypt, and in the parts of Libya about Cyrene, and strangers of Rome, Jews and proselytes,
11 Cretes and Arabians, we do hear them speak in our tongues the wonderful works of God.
12 And they were all amazed, and were in doubt, saying one to another, What meaneth this?
13 Others mocking said, These men are full of new wine.