When that sound was heard, a crowd gathered and stood bewildered, because each one heard them speaking in his own language.
In context
4and they were all filled with the Holy Spirit and began to speak in other tongues, as the Spirit gave them the words. 5Now there were devout Jews living in Jerusalem, from every nation under heaven. 6When that sound was heard, a crowd gathered and stood bewildered, because each one heard them speaking in his own language. 7Astonished and amazed, they said, “Aren’t all these men who are speaking Galileans? 8Then how is it that each of us hears them in the language of his own birth?