Peter has to explain that these people aren't drunk; it's still morning after all. No, this is the prophesied Spirit of God as one can find mentioned in Joel when he discusses the last days. Thanks to the Spirit, now people can actually hear each other and come together in common purpose.
It reminds us of the great story of the Tower of Babel. The last of the "pre-historic" stories in Genesis 11 depicts unified language and thought among people. They use this capability to exploit a new technology - brick-making - and build a city with the ambitious goal of constructing a tower to reach heaven itself.
God comes down to check it out and is appalled at this project and the prospect of humanity coming to God's abode. Together with the other gods in the heavenly council, God scrambles languages and scatters the concentrated humans across the world. End of problem.
So, why does God unite all people once again in the work of the Holy Spirit at Pentecost? How is this different from the plan for Tower of Babel? Doesn't this invite humanity to embrace and exercise the same hubris as before?
I wish I had a sermon video to share, but someone forgot to bring the video camera to church with him. So, below is the sermon text if you care to plow through it. Sorry. We promise to do better next week.