An herald: it is likely there were many heralds at the head of that great concourse, else they could not all hear. People, nations, and languages: proclamation was made therefore in several languages, to some of several nations assembled there, and to the representatives of all.
Related Commentaries of Daniel 3:4
Daniel 3:4
4 Then an herald cried aloud,a To you it is commanded, O people, nations, and languages,