The Chaldeans speak with great confidence. The king hasn’t asked for an interpretation yet, but neither has he told them the dream, and yet he has summed them all to stand before him and that is surely to have the dream explained.
A section of the Book of Daniel (as also a section of Ezra) beginning at the second half of verse 4 of chapter 2 is in Aramaic (called Syriack by the KJV), and does not return to Hebrew until chapter 8 verse 1. This is probably because of the international significance of the material and because it is intended for all – Aramaic being the language of the Chaldean Empire.