Why did the crowd think St Peter was drunk? An exercise in applied sociolinguistics

Extract

... And they were all filled with the Holy Spirit, and began to speak in other tongues, as the Spirit gave them utterance. Now there were dwelling in Jerusalem Jews, devout men from every nation under heaven. And at this sound the multitude came together, and they were bewildered, because each one heard them speaking in his own language. And they were amazed and wondered, saying, ‘Are not all these who are speaking Galileans? And how is it that we hear, each of us in his own native language? Parthians and Medes and Elamites and residents of Mesopotamia, Judaea and Cappadocia, Pontus and Asia, Phrygia and Pamphylia, Egypt and the parts of Libya belonging to Cyrene, and visitors from Rome, both Jews and proselytes, Cretans and Arabians, we hear them telling in our own tongues the mighty works of God. And all were amazed and perplexed, saying to one another, ‘What does this mean?’ But others mocking said, They are filled with new wine’. But Peter, standing with the eleven, lifted up his voice and addressed them, ‘Men of Judaea and all who dwell in Jerusalem, let this be known to you, and give ear to my words. For these men are not drunk, as you suppose, since it is only the third hour of the day ... ’

People have puzzled over the nature of the miracle reported in Acts 2 for centuries, and the passage is especially intriguing if you are a linguist. Did Peter really find himself speaking in languages he did not know?