The Holy Spirit came and enabled the disciples to speak other languages.

Acts 2:1-4

2 On the day when the Jews were celebrating the Pentecost festival, the believers were all together in one place in Jerusalem. 2 Suddenly they heard a noise coming from the sky that sounded like a strong wind. Everyone in the entire house where they were sitting heard the noise. 3 Then they saw what looked like flames of fire. These flames separated from one another, and one of them came down on the head of each of the believers. 4 Then all of the believers were ◄completely controlled/empowered► by the Holy Spirit {the Holy Spirit ◄completely controlled/empowered► all of the believers}, and he enabled them to begin speaking other languages [MTY] that they had not learned.