When the day of Pentecost arrived, they were all together in one place. And suddenly there came from heaven a sound like a mighty rushing wind, and it filled the entire house where they were sitting. And divided tongues as of fire appeared to them and rested on each one of them. And they were all filled with the Holy Spirit and began to speak in other tongues as the Spirit gave them utterance.
Now there were dwelling in Jerusalem Jews, devout men from every nation under heaven. And at this sound the multitude came together, and they were bewildered, because each one was hearing them speak in his own language. And they were amazed and astonished, saying, "Are not all these who are speaking Galileans? And how is it that we hear, each of us in his own native language? Parthians and Medes and Elamites and residents of Mesopotamia, Judea and Cappadocia, Pontus and Asia, Phrygia and Pamphylia, Egypt and the parts of Libya belonging to Cyrene, and visitors from Rome, both Jews and proselytes, Cretans and Arabians—we hear them telling in our own tongues the mighty works of God." And all were amazed and perplexed, saying to one another, "What does this mean?" But others mocking said, "They are filled with new wine."
Now when they heard this they were cut to the heart, and said to Peter and the rest of the apostles, "Brothers, what shall we do?" And Peter said to them, "Repent and be baptized every one of you in the name of Jesus Christ for the forgiveness of your sins, and you will receive the gift of the Holy Spirit. For the promise is for you and for your children and for all who are far off, everyone whom the Lord our God calls to himself." (ESV)
In Pentecostal churches, people receive the baptism of the Holy Spirit, the initial evidence of which is speaking in tongues. If you don't have tongues, you don't have the baptism - based on this passage of Scripture.
You are saved (first act of grace) and then you speak in a language that nobody but God can understand (second act of grace).
But...let's read the Scripture...
The people who had received the Holy Spirit began to speak in other tongues...yes. But...at the sound, devout men from "every nation" came together and each of them heard in his own language. Those who were there spoke in tongues and the other believers heard in tongues. Who were the ones who did not hear in their own tongues? The mockers...unbelievers.
The "moral" of the story? If somebody around you is "baptized with the Holy Spirit as a second work of grace", and you can't understand - you cannot hear in your own tongue...
you may not be one of the saved. It bears thinking about when coveting the gift.