Who were the disciples who spoke in tongues at Pentecost, and what was their background?
At Pentecost the speakers were Jewish disciples, likely the twelve apostles and possibly the entire hundred and twenty gathered. Most came from Galilee and were uneducated fishermen, including Peter. They were enabled by the Holy Spirit to speak known foreign languages to the Jewish crowd.
Les explains that Pentecost had nothing to do with Gentiles; it was Jewish. He notes the tongues were other languages, not an unknown guttural noise, because Jews from Babylon, Spain, and across the displaced world spoke different languages. The miracle was God giving the apostles, probably the twelve and maybe the whole hundred and twenty, the ability to speak those known languages. Peter and most of the disciples came from Galilee, were uneducated fishermen, yet suddenly spoke languages outside their own education.
And they were all amazed and marvelled, saying one to another, Behold, are not all these which speak Galilaeans?