Pentacost is not the issue. Whether those same gifts that the Church once had, and the early Church admits disappeared, are still valid today is the issue.
http://www.middletownbiblechurch.org/doctrine/charis35.htm
15. Can unsaved people speak in tongues?
The Biblical gift of tongues was the supernatural ability to speak in a foreign language which the speaker had never learned. An unsaved person would not have the God-given ability to do this. Spiritual gifts are given to believers at the point of salvation, not to unbelievers.
The modern day phenomena of speaking ecstatic utterances (glossolalia) is something quite different. There are countless examples of unsaved people speaking in tongues. Here are but a few:
1) In the second century the Montanists spoke in tongues. This was a heretical group especially noted for their heresies concerning the Holy Spirit. The following is a description of Montanus and his followers by Eusebius in his History of the Church:
Montanus, in his unbridled ambition to reach the top, laid himself open to the adversary, was filled with spiritual excitement and suddenly fell into a kind of trance and unnatural ecstasy. He raved, and began to chatter and talk nonsense, prophesying in a way that conflicted with the practice of the Church handed down generation by generation from the beginning. Of those who listened at that time to his sham utterances some were annoyed, regarding him as possessed, a demoniac in the grip of a spirit of error, a disturber of the masses. They rebuked him and tried to stop his chatter, remembering the distinction drawn by the Lord, and His warning to guard vigilantly against the coming of false prophets....Then he secretly stirred up and inflamed minds closed to the true Faith, raising up in this way two others—women whom he filled with the sham spirit, so that they chattered crazily, inopportunely, and wildly, like Montanus himself.
According to Eusebius, this practice of tongues speaking was totally contrary to the practice of the Church. Indeed, Montanus and his followers were excommunicated from the Church.
2) Irenaeus wrote the following concerning the second century heretic Marcus:
Marcus to a woman, "Receive first from me and by me the gift of Charis..." Woman: "I have never at any time prophesied, nor do I know how to prophesy." Marcus: "Open thy mouth, speak whatsoever occurs to thee, and thou shalt prophesy." She then, vainly puffed up and elated by these words, and greatly excited in soul by the expectation that it is herself who is to prophesy, her heart beating violently (from emotion), reaches the requisite pitch of audacity, and idly as well as impudently utters some nonsense as it happens to occur to her, such as might be expected from one healed by an empty spirit" (IRENAEUS AGAINST HERESIES).
The orthodox leaders of the early church recognized that such emotional outbursts of tongues speaking were not of God. It was a phenomena encouraged by the heretics.
3) The Cevenol priests who lived in France in the late 17th century also spoke in tongues. They were branded heretics because their prophecies went unfulfilled.
4) The Shakers originated in 1747 by a woman. Doctrinally she was all mixed up and held heretical views especially concerning the Person of Christ. "It is said that in order to mortify the flesh she instituted the practice of men and women dancing together naked while they spoke in tongues."
5) Examples of speaking in tongues are found within the Mormon church (cult): "Right from the beginning with Joseph Smith, Mormons have accepted tongues as a valid gift for modern times. When their temple was dedicated in Salt Lake City, hundreds of elders spoke in tongues."
6) The followers of Edward Irving (19th century) spoke in tongues. These people had revelations that contradicted Scripture, prophecies that went unfulfilled and promoted various erroneous teachings.
7) Today it is a known fact that people who do not even profess to be Christians speak in tongues:
Today shamans (witch doctors, priests, or medicine men) in Haiti, Greenland, Micronesia, and countries of Africa, Australia, Asia, and North and South America speak in tongues. Several groups use drugs to aid in inducing the ecstatic state and utterances. Voodoo practitioners speak in tongues. Buddhist and Shinto priests have been heard speaking in tongues. Moslems have spoken in tongues, and an ancient tradition even reports that Mohammed himself spoke in tongues.
8) Sad to say, there are many people today involved in the modern Charismatic movement who have spoken in tongues and yet they do not have any clear understanding of salvation or the gospel of grace or what it means to be born again. They have had an experience but they do not have eternal life (1 John 5:11-12).
APPENDIX ONE
THE TONGUE SPEAKING OF THE MONATISTS
Eusebius: The History of the Church, Penguin Classics version c.1965 pp.218-219
"After completing his explanation on these lines at the beginning of his book, He goes on to describe the originator of this heretical sect, as follows.
Their opposition and their recent schismatic heresy in relation to the Church originated thus. There is, it appears, a village near the Phrygian border of Mysia called Ardabau. There it is said that a recent convert named Montanus, while Gratus was proconsul of Syria, in his unbridled ambition to reach the top laid himself open to the adversary, was filled with spiritual excitement and suddenly fell into a kind of trance and unnatural ecstasy. He raved, and began to chatter and talk nonsense, prophesying in a way that conflicted with the practice of the Church handed down generation by generation from the beginning. Of those who listened at that time to his sham utterances some were annoyed, regarding him as possessed, a demonaic in the grip of the spirit of error, a disturber of the masses. The rebuked him and tried to stop his chatter, remembering the distinction drawn by the Lord, and His warning to guard vigilantly against the coming of false prophets. Others were elated as if by the Holy Spirit or a prophetic gift, were filled with conceit, and forgot the Lord's distinction. They welcomed a spirit that injured and deluded the mind and led the people astray: they were beguiled and deceived by it, so that it could not now be reduced to silence. By some art, or rather by methodical use of malign artifice, the devil contrived the ruin of the disobedient, and was most undeservedly honored by them. Then he secretly stirred up and inflamed minds closed to the true faith, raising up in this way two others--women who he filled up with this sham spirit, so that they chattered crazily, inopportunely, and wildly, ;like Montanus himself. On those who were elated and exultant about him the spirit bestowed favors, swelling their heads with his extravagant promises. Sometimes it reproved them pointedly and convincingly to their faces, to avoid appearing uncritical---though few of the Phrygians were deceived. They were taught by this arrogant spirit to denigrate the entire Catholic (universal) Church throughout the world, because the spirit of pseudo-prophecy received neither honor nor admission into it; for the Asian believers repeatedly and in many parts of Asia had met for this purpose, and after investigating the recent utterances pronounced them profane and rejected the heresy. Then at last its devotees were turned out of the Church and ex-communicated.
(Continuing on page 221)
When all their arguments have been disposed of and they have nothing to say, they try to take refuge in the martyrs, alleging that they have a great number and that this is convincing proof of the power of what in their circle is called the prophetic spirit. But this seems to be as false as false can be, for some of the other heretical sects have immense numbers of martyrs, but this is surely no reason why we should approve of them or acknowledge that they have the truth. To take one instance--those who as sectaries of Marcion are called Marcionites claim an immense number of Christian Martyrs, but they do not truly acknowledge Christ Himself. . . Hence whenever members of the Church called to martyrdom for the true faith meet any of the so-called martyrs of the Phrygian sect, they part company with them and have nothing to do with them till their own fulfillment, because they will not be associated with the spirit that spoke through Montanus and the women. That this is true, and that it occurred in our own time in Apamea on the Maeander, in the case of Gaius and Alexander and the other martyrs from Eumenia, is perfectly clear.
IRENAEUS, CONCERNING THE HERETIC MARCUS (2nd CENTURY)
Marcus to a woman,"Receive first from me and by me the gift of Charis. . . Woman,"I have never at any time prophesied, nor do I know how to prophesy"
Marcus,"Open thy mouth, speak whatever occurs to thee, and thou shalt prophesy."
She then, vainly puffed up and elated by these words, and greatly excited in soul by the expectation that it is herself who is to prophesy, her heart beating violently (from emotion), reaches the requisite pitch of audacity, and idly as well as impudently utters some nonsense as it happens to occur to her, such as might be expected from one heated by an empty spirit." (Irenaeus Against Heresies)