Speaking In Tongues

From the Biblical point of view, the word translated as tongue in English originates from two New Testament Greek words:

• dialektos from which we get the word dialect, meaning a recognized language.
• glossa, meaning the tongue, but through actual usage, describing the speaking of a language for communication between people.

On that now-famous Pentecost, known as the "birthday of the church," many people suddenly began to "speak in tongues" as The Holy Spirit enabled them. But, they spoke in real languages that natives of each particular language could understand -

"All of them were filled with the Holy Spirit and began to speak in other tongues as The Spirit enabled them. Now there were staying in Jerusalem God-fearing Jews from every nation under heaven. When they heard this sound, a crowd came together in bewilderment, because each one heard them speaking in his own language. Utterly amazed, they asked: "Are not all these men who are speaking Galileans? (see Galilee) Then how is it that each of us hears them in his own native language? Parthians, Medes and Elamites; residents of Mesopotamia, Judea and Cappadocia, Pontus and Asia, Phrygia and Pamphylia, Egypt and the parts of Libya near Cyrene; visitors from Rome, both Jews and converts to Judaism; Cretans and Arabs - we hear them declaring the wonders of God in our own tongues!" (Acts 2:4-11)

The ability to speak in tongues, other languages, was a gift that God gave to some so that the Gospel could be preached to those nations. The "tongues" were actual languages -

"Now, brothers, if I come to you and speak in tongues, what good will I be to you, unless I bring you some revelation or knowledge or Prophecy or word of instruction? Even in the case of lifeless things that make sounds, such as the flute or harp, how will anyone know what tune is being played unless there is a distinction in the notes? Again, if the trumpet (see The Shofar) does not sound a clear call, who will get ready for battle? So it is with you. Unless you speak intelligible words with your tongue, how will anyone know what you are saying? You will just be speaking into the air. Undoubtedly there are all sorts of languages in the world, yet none of them is without meaning. If then I do not grasp the meaning of what someone is saying, I am a foreigner to the speaker, and he is a foreigner to me." (1 Corinthians 14:6-11)

Fact Finder: Is speaking in tongues for instruction and prophecy?
1 Corinthians 14:6