Acts 2:4b

⁴ And they were all filled with the Holy Spirit and began to speak with other tongues, as the Spirit gave them utterance.

and began to speak with other tongues [languages],

Tongues here were foreign languages, not some unique language from heaven. These were not ecstatic speeches coming from an experience of something like catalepsy, beyond the control of the speaker. These languages were understood by various groups assembled in Jerusalem for Pentecost. Thus, they were extant, known languages of that day.

The “other tongues” are languages other than the native speaker’s language. There is an estimation of 120,000 Jewish pilgrims from different nations attending Pentecost (e.g., Parthians, Medes, Elamites).

as the Spirit gave them utterance.

Speaking in tongues was a miracle of speaking in a foreign language without learning it (Acts 2:6-11).

PRINCIPLE:

The church is an organism, not an organization or national entity.

APPLICATION:

Before Acts 2, the church was anticipated (Mt 16:18). The nation Israel was an organization, a national entity, whereas the church is an organism, a body (1 Co 12:13). The baptism of the Spirit launched an entirely new economy in God’s arrangement for His people, the church.

The Bible never challenges people to seek the baptism of the Spirit, but it commands us to be filled with the Spirit. The baptism of the Spirit is a non-repeatable, single event in the person who believes in Christ. However, the filling of the Spirit is repeatable and depends on yielding oneself to the control of the Spirit (Eph 5:18; Acts 4:8, 31; 6:5; 7:55; 9:17; 13:9). Ephesians 5:18 commands the Christian to be constantly filled or controlled by the Spirit. Our passage associates speaking in foreign languages with the filling of the Spirit, not the baptism of the Spirit.

1. Speaking in tongues in our passage associates the idea with the filling of the Spirit, not the baptism of the Spirit.
2. Tongues in Acts 2 were known, extant languages, not ecstatic utterances. The use of dialektos in verses 6 and 8 cannot refer to anything other than a known language or dialect.
3. Acts 2:5-12 emphasizes that people from different geographical locations understood the message in their own language.
4. Speaking in tongues is not the typical response to the filling of the Spirit. There are passages where people spoke in foreign languages without being filled with the Spirit (Acts 4:8, 31; 6:5; 7:55; 9:17; 13:9).
5. Speaking in tongues was not a characteristic of being filled with the Spirit (Eph 5:18ff).
6. The purpose of speaking in tongues was to testify to non-believing Israelites (1 Co 14:21-22). It was a “sign” to Israel that Christianity was true.
7. Tongues were also a sign to show Israel that Jews, Gentiles, and Samaritans were all part of the family of God (Acts 15:8–9).
8. The Samaritans received the Holy Spirit but did not speak in tongues (Acts 8:14–19).
9. Acts 10:44–47 describes the receiving of the Spirit by the Gentiles of Cornelius’s household associated with speaking in different languages. That event convinced the Jewish believers that the Gentiles had received the Spirit too (Acts 10:45, 47). 
10. John the Baptist’s disciples were the last group to speak in tongues (Acts 19:1–7). They were technically the last remnants of Old Testament saints who came to faith in Christ. God gave them the ability to speak in languages to demonstrate their full equality with Jews, Samaritans, and Gentiles in the church.
11. Each case of speaking in tongues describes a unique, historical transition from the economy of Israel to the church.
12. The phenomenon of speaking in tongues passed with the cessation of the apostles. Miracles passed after their cessation (He 2:3-4).
13. There is no indication in Scripture that tongues had anything to do with believers other than to show that God was transitioning from the economy of Israel to that of the church.
14. God had established the church and transitioned from Israel as His economy for believers. First Corinthians 13:8 explicitly says that “tongues will cease.” “Speaking in tongues” was unknown in the post-apostolic era and even in later New Testament books. The only exception was that a heretical group spoke in tongues (Montanism).