Jamieson, Fausset and Brown on Daniel 5:11

11. spirit of the holy gods--She remembers and repeats Nebuchadnezzar's language (Da 4:8, 9, 18). As Daniel was probably, according to Oriental custom, deprived of the office to which Nebuchadnezzar had promoted him, as "master of the magicians" (Da 4:9), at the king's death, Belshazzar might easily be ignorant of his services.

the king ... thy father the king ... thy father--The repetition marks with emphatic gravity both the excellencies of Daniel, and the fact that Nebuchadnezzar, whom Belshazzar is bound to reverence as his father, had sought counsel from him in similar circumstances.