Speaking languages of man

[Acts 2:1] And when the day of Pentecost was fully come, they were all with one accord in one place.
Day of Pentecost - in Ex. 19-20 when the Israelites came to Mount Sinai. Accompanied by peals of thunder and bursts of lightning, the powerful word of G-d with sparks flying out. Fiery sparks flew in every direction -- symbolizing that each divine utterance was heard in every language. They were like tongues of fire. G-d’s awesome presence was made known as He revealed His will to the people He loved. G-d’s revelation in Torah was given to His people. Pentecost is the “time in which G-d gave us our Torah. Pentecost occurred on the 15th day after Passover. (Lev. 23:15, 16).
With one accord - the solemnity of the day, perhaps, unconsciously raising their expectations.
[2] And suddenly there came a sound from heaven as of a rushing mighty wind, and it filled all the house where they were sitting.
Rushing mighty wind - "The whole description is so picturesque and striking that it could only come from an eye-witness". The suddenness, strength, and diffusiveness of the sound strike with deepest awe the whole company, and thus complete their preparation for the heavenly gift. Wind was a familiar emblem of the Spirit (Ezek. 37:9; John 3:8; 20:22). But this was not a rush of actual wind. It was only a sound "as of" it.
House - has often associated with the upper room, it is much more likely that the site of the miracle of Pentecost was the Temple. House referrers to the house of the L-rd, where they would have been sitting for the study of Torah. The Temple was the meeting place of G-d’s people for the Feast of Pentecost. In verse 46, they gathered in the Temple with one accord each day to pray, study, and learn. There was a monumental stairway that led up to a wide platform area, pilgrims would ritually immerse in baptismal pools and ascend the steps to the platform, where they could ender through the Hula gates into the portico of the Temple these spacious area served as meeting places for the study of Torah.
[3] And there appeared unto them cloven tongues like as of fire, and it sat upon each of them.
Cloven tongues - The words of Torah appeared to the people in fire. They saw the flames and heard the voice in their own language. The tongues of fire are paralleled by Jewish descriptions of the theophany at Sinai.
Like as of fire - disparted tongues," that is, tongue-shaped, flame-like appearances, rising from a common center or root, and resting upon each of that large company: beautiful visible symbol of the burning energy of the Spirit now descending in all His plenitude upon the Messianic Church, and about to pour itself through every tongue, and over every tribe of men under heaven!
[4] And they were all filled with the Holy Ghost, and began to speak with other tongues, as the Spirit gave them utterance.
They - Visitors from all parts of the world who had made pilgrimage to Jerusalem heard the early believers speaking about the wonderful works of G-d in the different languages of the nations. They witnessed the tongues of fire resting on the heads of those filled with the Spirit. Pentecost is thus a point of convergence where the spiritual force of G-d’s blessing has dramatically impacted both Judaism and Christianity. While the name itself simply means fifty days, referring to the seven weeks plus one day for the Harvest of Grains, for Jews and Christians. The outpouring of the Holy Spirit calls for service. Torah’s revelation and the Holy Spirit’s fire revive the faithful to meet the challenge.
Began to speak with other tongues - real, living languages, as is plain from what follows. The thing uttered, probably the same by all, was "the wonderful works of
G-d," perhaps in the inspired words of the Old Testament evangelical hymns; though it is next to certain that the speakers themselves understood nothing of what they uttered (see on 1 Cor. 14:1-25).
[8] And how hear we every man in our own tongue, wherein we were born?
People from all over the world who came from different cultures, speaking languages foreign to the inhabitants of the land of Israel. Pilgrims and proselytes from all over the world heard the people speaking in foreign languages. Even though the apostles had never learned these languages, they spoke to the visitors to Jerusalem in their native dialects.