Speaking in tongues
This article is one in a series of studies on the Holy Spirit and the baptism of the Holy Spirit - you are currently on the topic that is in bold:
What the Bible teaches
Because there were several cases in Acts where people received the new covenant power of the Holy Spirit and began to speak with tongues at the same time (Acts 2:4; 10:46; 19:6; probably also implied in 8:17–19 because of the parallel with the experience of the disciples in Acts 2), Pentecostal teaching has commonly maintained that the outward sign of baptism in the Holy Spirit is speaking in tongues (that is, speaking in languages that are not understood by and have not been learned by the person speaking, whether known human languages or other kinds of angelic or heavenly or miraculously given languages).
But it is important to realize that there are many cases where being filled with the Holy Spirit did not result in speaking in tongues. When Jesus was filled with the Spirit in Luke 4:1, the result was strength to overcome the temptations of Satan in the wilderness. When the temptations were ended, and Jesus “returned in the power of the Spirit into Galilee” (Luke 4:14), the results were miracles of healing, casting out of demons, and teaching with authority. When Elizabeth was filled with the Holy Spirit, she spoke a word of blessing to Mary (Luke 1:41–45). When Zechariah was filled with the Holy Spirit, he prophesied (Luke 1:67–79). Other results of being filled with the Holy Spirit were powerful preaching of the gospel (Acts 4:31), (perhaps) wisdom and Christian maturity and sound judgment (Acts 6:3), powerful preaching and testimony when on trial (Acts 4:8), a vision of heaven (Acts 7:55), and (apparently) faith and maturity of life (Acts 11:24). Several of these cases may also imply the fullness of the Holy Spirit to empower some kind of ministry, especially in the context of the book of Acts, where the empowering of the Holy Spirit is frequently seen to result in miracles, preaching, and works of great power.
Therefore, while an experience of being filled with the Holy Spirit may result in the gift of speaking in tongues, or in the use of some other gifts that had not previously been experienced, it also may come without the gift of speaking in tongues. In fact, many Christians throughout history have experienced powerful infillings of the Holy Spirit that have not been accompanied by speaking in tongues. With regard to this gift as well as all other gifts, we must simply say that the Holy Spirit “apportions each one individually as he wills” (1 Cor. 12:11).