"And there were dwelling in Jerusalem Jews, devout men, from every nation under heaven. And when this sound occurred, the multitude came together, and were confused, because everyone heard them speak in his own language. Then they were all amazed and marveled, saying to one another, 'Look, are not all these who speak Galileans? And how is it that we hear, each in our own language in which we were born? Parthians and Medes and Elamites, those dwelling in Mesopotamia, Judea and Cappadocia, Pontus, and Asia, Phrygia and Pamphylia, Egypt and the parts of Libya adjoining Cyrene, visitors from Rome, both Jews and proselytes, Cretans and Arabs--we hear them speaking in our own tongues the wonderful works of God. So they were all amazed and perplexed, saying to one another, 'Whatever could this mean?' Others mocking said, 'They are full of new wine'" (Acts 2:5-13).
Luke informs us that there were devout Jews from every part of the Mediterranean world gathered at Jerusalem at this time. To be "devout" means to be cautious in order to avoid offending God. These men were careful to observe His commandments, which is why they had traveled very far in many cases to be in Jerusalem for Pentecost. They were among the best adherents to Judaism. When they heard the sound as of a rushing mighty wind and the apostles speaking, a large group of people came together (at least several thousand and perhaps in the tens of thousands; cf. 2:41). The people were perplexed and filled with wonder when they heard the apostles speak in the languages of the people assembled. Luke explicitly stated - "Everyone heard them speak in his own language" (2:6). The apostles were not uttering gibberish. They were fluently speaking languages they had never studied before. The miracle was in the speaking, not in the hearing. Some scholars believe there would have been at least seven or eight major languages represented on that day as well as several less used dialects. The people, who were not expecting this, were amazed! What really was happening? What did this all mean? How could these men, being Galileans (who were often looked down upon as being ignorant, rude, and uncivilized; cf. John 1:46; 7:52), speak in these various languages that were represented on that day? How could they communicate "the wonderful works of God" (2:11) in such a variety of languages they had never studied or spoken before? The answer: the Holy Spirit empowered them to do so!
Although many were curious as to how the apostles were able to accomplish this impressive feat, some scoffed and ridiculed that which they could not explain (such is still a common tactic today). Unfortunately for the apostles and the early church, this unseemly attitude was but a preview of things to come.
Those who mocked the apostles affirmed - "they are full of new wine" (2:13). A better rendering here would be "sweet wine," which is not a reference to the age of the beverage but to the fact that it was made from the very purest juice of the grape. In other words, some (perhaps the scribes and Pharisees?) believed the apostles were drunk! If one did not listen carefully (or simply did not want to believe the miracle that was being demonstrated), he might not discern the voice of the apostle that was speaking God's truth in his own particular language. If one only paid attention to the apostles speaking in other foreign languages (and not one's own language), he might come to the wrong conclusion about the sobriety of the speakers.