This answer relates only to the comprehensible tongues recorded in Acts. It does not relate to the incomprehensible tongues Paul mentions in 1 Corinthians 14.
2 For anyone who speaks in a tongue does not speak to people but to God. Indeed, no one understands them; they utter mysteries by the Spirit. (1 Corinthians 14:2 NIV)
This verse is confirmed several times later in the same chapter, but immediately it is clear that the Corinth tongues are not the same as the comprehensible tongues in Acts 2:8-10.
How many times did real tongues occur in Acts?
Acts 2:8 Then how is it that each of us hears them in our native language? 9 Parthians, Medes and Elamites; residents of Mesopotamia, Judea and Cappadocia, Pontus and Asia,[b] 10 Phrygia and Pamphylia, Egypt and the parts of Libya near Cyrene; visitors from Rome 11 (both Jews and converts to Judaism); Cretans and Arabs—we hear them declaring the wonders of God in our own tongues!” (NIV)
Acts 2:46 For they heard them speaking in tongues[b] and praising God. Then Peter said, 47 “Surely no one can stand in the way of their being baptized with water. They have received the Holy Spirit just as we have.” 48 So he ordered that they be baptized in the name of Jesus Christ. Then they asked Peter to stay with them for a few days. (NIV)
Acts 11:15 “As I began to speak, the Holy Spirit came on them as he had come on us at the beginning.
Acts 19:4 Paul said, “John’s baptism was a baptism of repentance. He told the people to believe in the one coming after him, that is, in Jesus.” 5 On hearing this, they were baptized in the name of the Lord Jesus. 6 When Paul placed his hands on them, the Holy Spirit came on them, and they spoke in tongues and prophesied. 7 There were about twelve men in all.
Acts 8:14 When the apostles in Jerusalem heard that Samaria had accepted the word of God, they sent Peter and John to Samaria. 15 When they arrived, they prayed for the new believers there that they might receive the Holy Spirit, 16 because the Holy Spirit had not yet come on any of them; they had simply been baptized in the name of the Lord Jesus. 17 Then Peter and John placed their hands on them, and they received the Holy Spirit. 18 When Simon saw that the Spirit was given at the laying on of the apostles’ hands, he offered them money 19 and said, “Give me also this ability so that everyone on whom I lay my hands may receive the Holy Spirit.” (NIV)
So on the balance of what Luke records in all four incidents there seems to be a consistency that tongues (and not healings) occurred each of the four times the ‘circle of baptism’ was enlarged.