On the Day of Pentecost in Acts chapter 2 many languages were heard as people praised the Lord in their prayer languages, but when Peter spoke he spoke in a common language that folks from all over the Roman Empire could understand. That language would be Greek. In the local synagogues in Jerusalem, Judea, and Samaria they spoke Aramaic and Greek. When Paul would preach in synagogues as he made his missionary journeys, I assume he spoke Greek.
As far as baptism, we have no record of a baptism in our New Testament which quotes the words being spoken during the ritual. Early Christian baptism was probably a threefold self immersion like the mikveh from which it came.
The 3000 who were baptized in
Acts 2 probably self immersed in the mikveh pools that were there outside the Temple. In
Acts 8 we do read that both Philip and the Ethiopian went down into the water and Philip immersed him. So, very early in the church we can find both the one being baptized and the one doing the baptism both going into the water.