The Holy Spirit appeared suddenly, loudly, and effectively. The reaction was mixed. Some were bewildered, amazed, astonished.
Even when they found themselves able to understand in their own languages what the recipients were saying, the first witnesses either didn't know what was happening or made up a reason that seemed reasonable--they must be drunk.
Miracles or any exciting phenomena do not necessarily generate faith.
Peter responded to the lack of understanding and the rude remark by preaching a sermon.
Nonbelievers will not agree with our explanations. At least right away. After all, why should they? Allowing experience to explain phenomena is not unexpected.
Be careful with those sermons. They don't always help the unbeliever. At least right away.
I'm wondering what fraction of the people listening to a sermon on any Sunday are unbelievers. I'm wondering what they think about what they see happening that we explain has come through the Lord.