Due to a controversy within the Southern Baptist Convention, the blogosphere has recently been lit up with the subject of private prayer language and speaking in tongues. The New Testament gift of tongues is the ability to speak in a human language that the speaker has never learned. The historical records of the exercise of the gift of tongues is found in Acts 2, 10, and 19.
I agree with those Southern Baptists who disagree with the modern practice of private prayer language and speaking in tongues. An example of the legitimate exercise of the gift of tongues would be preaching the gospel in a language one has never studied or learned. In promoting this position, some have suggested that tongues is/was "an evangelistic tool". Here I differ.
Let us consider tongues as an evangelistic tool. Tongues seems to be a sign verifying the preached word, rather than a tool necessary for communicating the word. In the three instances in Acts the person(s) preaching the gospel appear to have been able to communicate with the hearers of the gospel in a common language and therefore did not need to speak another language for the purpose of communicating.
1. In Acts 2, Jews and Jewish proselytes were present from Europe, Asia, and Africa and each heard some of the apostles speak in his/her own language. But this is much more likely for a sign rather than the only way the apostles could communicate with them. Notice verses 7 and 12 -- "saying one to another." The assembled people were able to speak to one another in a common language, so the tongues appear to be for a sign rather than an evangelistic tool (i.e., the only way the apostles could communicate with them), since they could communicate in a common language.
Acts 2:4-13 -- And they were all filled with the Holy Ghost, and began to speak with other tongues, as the Spirit gave them utterance. And there were dwelling at Jerusalem Jews, devout men, out of every nation under heaven. Now when this was noised abroad, the multitude came together, and were confounded, because that every man heard them speak in his own language. And they were all amazed and marvelled, saying one to another, Behold, are not all these which speak Galilaeans? And how hear we every man in our own tongue, wherein we were born? Parthians, and Medes, and Elamites, and the dwellers in Mesopotamia, and in Judaea, and Cappadocia, in Pontus, and Asia, Phrygia, and Pamphylia, in Egypt, and in the parts of Libya about Cyrene, and strangers of Rome, Jews and proselytes, Cretes and Arabians, we do hear them speak in our tongues the wonderful works of God. And they were all amazed, and were in doubt, saying one to another, What meaneth this? Others mocking said, These men are full of new wine.
Something similar to this might be the instance of an English speaker preaching in Montreal, Quebec, Canada. A number of the people probably would be able to understand if he preached in English. But if this person, obviously untrained in French, were to suddenly begin speaking in French, it would be a marvelous sign for the hearers (and the speaker!). On the other hand, if the speaker suddenly began saying something that sounded like "hominy, hominy, hominy, goulash, hominy, hominy," none would see a verifiable sign other than those already religiously acculturated to think such was "speaking in tongues."
2. In Acts 10, Peter quite obviously converses with Cornelius and preaches to Cornelius' household in a common language. The speaking in tongues does not occur until after Peter's sermon, and it appears that it is the believers of Cornelius household that do the tongues speaking; therefore, making it a sign that they "have received the Holy Ghost as well as we" rather than an evangelistic tool.
Acts 10:44-48 -- While Peter yet spake these words, the Holy Ghost fell on all them which heard the word. And they of the circumcision which believed were astonished, as many as came with Peter, because that on the Gentiles also was poured out the gift of the Holy Ghost. For they heard them speak with tongues, and magnify God. Then answered Peter, Can any man forbid water, that these should not be baptized, which have received the Holy Ghost as well as we? And he commanded them to be baptized in the name of the Lord. Then prayed they him to tarry certain days.
3. In Acts 19, Paul converses in a common language with the disciples he found in Ephesus. The speaking in tongues does not occur until after the disciples receive Paul's witness on the baptism of John, are baptized, and Paul lays his hands on them. It is the believers of Ephesus that do the tongues speaking; therefore, it appears to be a verification sign rather than an evangelistic tool.
Acts 19:1-7 -- And it came to pass, that, while Apollos was at Corinth, Paul having passed through the upper coasts came to Ephesus: and finding certain disciples, He said unto them, Have ye received the Holy Ghost since ye believed? And they said unto him, We have not so much as heard whether there be any Holy Ghost. And he said unto them, Unto what then were ye baptized? And they said, Unto John's baptism. Then said Paul, John verily baptized with the baptism of repentance, saying unto the people, that they should believe on him which should come after him, that is, on Christ Jesus. When they heard this, they were baptized in the name of the Lord Jesus. And when Paul had laid his hands upon them, the Holy Ghost came on them; and they spake with tongues, and prophesied. And all the men were about twelve.
I agree that speaking in tongues was speaking in a human language not studied or known by the speaker. I conclude that its value was as a sign rather than a necessity for communication.