Three times in a year all of your men shall appear before Jehovah your God in the place which He shall choose: The Feast of Unleavened Bread, Pentecost and the Feast of Tabernacles. Deuteronomy 16:16a
All devout Jewish men from every nation under heaven were camping in Jerusalem for Pentecost. Acts 2:5
When the day of Pentecost was fully come, the Apostles were all together in one place, suddenly there came a sound like that of a mighty rushing wind from heaven. It filled the whole house where they were staying.
Flames of fire in the shape of cloven tongues came and sat upon each of them. They were all filled with the Holy Spirit and began to speak with a different language as the Spirit gave them utterance. Acts 2:1-4
There are many different languages in the world. All have meaning. 1 Corinthians 14:10
How shall it be known what is spoken unless you utter by the tongue words that are easy to be understood? 1 Corinthians 14:9
“I will return a Holy and Pure language to the people.” [Jehovah] Zephaniah 3:9a