TONGUES

Speaking with tongues or "glossolalia," is a spiritual gift given to Believers. This gift is mentioned in Mark 16:17 by Jesus as a future gift.
Following the Resurrection and the giving of the Holy Spirit we find the gift came into use. When the Disciples were filled with the Holy Spirit on the Day of Pentecost, Acts 2:4 they were able to speak in other "tongues".
It is important to point out that the Greek word used can also be translated as "language," a language unknown to the person.
A second occurrence of the appearance of this gift is given in Acts 10:44-48.
God reveals by this action that the Holy Spirit was available to the Gentiles as well as to the Jews.

At the time of the event, Jerusalem was full of many Jews from the nations surrounding the Mediterranean, they would have spoken only in one of the languages of the area they normally lived in. It was possible that some may have spoken Greek, a common language around the Mediterranean, however, it is generally agreed that Luke, the writer of Acts, meant the word "glossolalia," to be understood as "speaking in a known foreign language, which was unknown to the speaker".

In both of the events, as recorded in Acts 2:8-11 and Acts 10:44-48, the Holy Spirit gave the Believers the ability to speak in another known language, but not known by the Believer speaking. The New Testament record shows that the people that were there were very obviously able to understand the words being used by the Disciples, at Pentecost they were speaking to the crowds, who could understand them, they were speaking in languages which were in common use. God gave the disciples this gift so that they could tell the Jews, who had come to Jerusalem from many nations for the Feast of Pentecost, the news of the Gospel.
This gift was given as a sign of the power and presence of God in the Believers and was for the benefit of the unbelievers during the early development of the church.

However, in 1 Corinthians 12 to 14 there is an indication that there was another type of "tongues" practiced in the early church, this use of the gift needed an interpreter to understand any words spoken in the "tongues", note that if there was no interpreter present then the person should remain silent, 1 Cor 14:27-28. What was the difference we ask? Unfortunately we are not told what the difference was but can only assume that the words used were not in a "known language," but in a "spiritual language".
Some modern scholars believe that the "glossolalia" of Acts 2:1-13 was the same as that described in 1 Corinthians 12 to 14, however there are differences. The "glossolalia," of Acts is different to that of Corinthia. In Jerusalem, Caesarea and Ephesus, whole companies, on whom the Holy Spirit fell, immediately spoke with the "glossolalia," while in the Corinthia churches it appears that the gift was only given to specific individuals and could be controlled by the speaker, 1 Cor 14:27,28. Paul actually used a different word, " phone " in the original ‘Letter to Corinthia,’ 1 Cor 12:10,11.

The gift, as recorded in Acts, appears to have affected the Believers for a short and temporary period. Note, it appears that the Believers could not resist the effect of the gift at the time. The occurrence of "tongues" recorded in Acts were understood by the hearers, suggesting a known language, but at Corinthia there was the need of an interpreter, the language was not normal.
The Corinthians were putting great emphasis upon the gift, often misusing the gift for their own desires, as a result Paul puts limits on the use of the gift in the church, 1 Cor 14:27-28.