When Saul was pursuing Christians to Damascus, trying to bring them back to Jerusalem, he met the Lord on the Damascus Road and was converted. He was struck blind, and then regained his sight when he met Ananias. (Acts 9:1-18)
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. Acts 2:1-4
Before the ascension of Jesus, He promised the empowerment of the Holy Spirit for His followers (Acts 1:8). The coming of the Holy Spirit unfolded in Acts 2 and the disciples were recorded to have spoken in other tongues when they were filled with the Spirit. More importantly, people gathered and heard their own native language being spoken. This gave Peter, one of the disciples, the opportunity to testify about Christ (Acts 2:14-41) leading to the conversion of 3,000 people.
This reminded me of when God confused the language of people as they were starting to build for themselves a city and tower (Gen 11:1-9). The multitude of languages we know of now will ultimately bring glory to God as more and more people confess the Lordship in Christ in their own tongue.