With other tongues (heterais glōssais). Other than their native tongues. Each one began to speak in a language that he had not acquired and yet it was a real language and understood by those from various lands familiar with them. It was not jargon, but intelligible language. Jesus had said that the gospel was to go to all the nations and here the various tongues of earth were spoken. One might conclude that this was the way in which the message was to be carried to the nations, but future developments disprove it. This is a third miracle (the sound, the tongues like fire, the untaught languages). There is no blinking the fact that Luke so pictures them. One need not be surprised if this occasion marks the fulfilment of the Promise of the Father. But one is not to confound these miraculous signs with the Holy Spirit. They are merely proof that he has come to carry on the work of his dispensation. The gift of tongues came also on the house of Cornelius at Caesarea (Act 10:44-47; Act 11:15-17), the disciples of John at Ephesus (Act 19:6), the disciples at Corinth (1 Corinthians 14:1-33). It is possible that the gift appeared also at Samaria (Act 8:18). But it was not a general or a permanent gift. Paul explains in 1Co 14:22 that “tongues” were a sign to unbelievers and were not to be exercised unless one was present who understood them and could translate them. This restriction disposes at once of the modern so-called tongues which are nothing but jargon and hysteria. It so happened that here on this occasion at Pentecost there were Jews from all parts of the world, so that some one would understand one tongue and some another without an interpreter such as was needed at Corinth. The experience is identical in all four instances and they are not for edification or instruction, but for adoration and wonder and worship.
As the Spirit gave them utterance (kathōs to pneuma edidou apophtheggesthai autois). This is precisely what Paul claims in 1Co 12:10, 1Co 12:28, but all the same without an interpreter the gift was not to be exercised (1Co 14:6-19). Paul had the gift of tongues, but refused to exercise it except as it would be understood. Note the imperfect tense here (edidou). Perhaps they did not all speak at once, but one after another. Apophtheggesthai is a late verb (lxx of prophesying, papyri). Lucian uses it of the ring of a vessel when it strikes a reef. It is used of eager, elevated, impassioned utterance. In the N.T. only here, Act 2:14; Act 26:25. Apophthegm is from this verb.