"They saw what seemed to be tongues of fire that separated and came to rest on each of them. All of them were filled with the Holy Spirit and began to speak in other tongues as the Spirit enabled them." NIV translation
These two verses, to me, are bringing home the same point. That point is that there is only one Spirit that is given to followers of Jesus Christ. Each one of us, in Christ, receive that same Spirit and the power that is associated with it. In the second verse, we see that, when they received the Spirit, that Spirit caused them to be able to speak in different languages (tongues). It seems that, today, we spend too much time in trying to take some course or other program to equip us to do God's work. I am afraid that we would probably say wait I have to take a language course at a Christian College first. In these verses, we see that, if we trust in God, He will do the work through us. Not in our own strength and skill but because of the Holy Spirit. Are you working in your own strength or in the Spirit?
"Now there were staying in Jerusalem God-fearing Jews from every nation under heaven." NIV translation
This verse reminds us that, in the beginning, the Jewish people were the only ones that had access to God. Even at this point, even though Jesus had came for all people, the time was not yet right for gentiles to be included. Isn't it amazing how God works? He has His timing and it is always perfect. Who knows why God had the early church to be all Jewish and to be persecuted? Today, you and I, though we may be different, can be added through the vine that is Jesus Christ.
"When they heard this sound, a crowd came together in bewilderment, because each one heard them speaking in his own language." NIV translation
Once again, we get to see the power of God through the Holy Spirit. You see, those that received the Spirit did not have to go to some place and study language for years. It was not a matter of what the people could do but what the Spirit could do through them. In your daily life, are you trusting in your knowledge and abilities or are you totally trusting in God?
"Utterly amazed, they asked "Are not all these men who are speaking Galileans?"" NIV translation
Once again, we see God showing his power through the Holy Spirit. When people are around you, do they get the feeling that there is something different? If you've got the Spirit, it will show and God will use you to change lives. That is what is happening in this verse.