I know it's not absolute, what I suggest based on what you propose here.
It's just I find it incredible a king would not have other translators of Hebrew Aramaic.
Cutting a long story short
Then all the king’s wise men came in, but they could not read the writing or tell the king what it meant. 9 So King Belshazzar became even more terrified and his face grew more pale. His nobles were baffled.
10 The queen,[
c] hearing the voices of the king and his nobles, came into the banquet hall. “May the king live forever!” she said. “Don’t be alarmed! Don’t look so pale! 11 There is a man in your kingdom who has the spirit of the holy gods in him.
As you can see none of kings wiseman could translate it.
Then we see suggestion it is only the the spirit of God that can translate this.
Which could mean the wisemen declared it an unknown language they had never seen.