1)
Why does "Mamlechos" have the prefix Hei? It is Samuch to "ha'Aretz"!
1.
Radak: Sometimes there is a Hei even though it is Samuch, e.g. "ha'Lishchos ha'Kodesh" (Yechezkel 46:19), "ha'Ysad ha'Ereg" (Shoftim 16:14) and a small number of other cases.
2)
What is "Sheshach"?
1.
Rashi: Sheshach is Bavel in At-Bash (we exchange the first, second, third... letters of the Aleph Beis with the first, second... letters from the end). Radak - also Yonason translates 'Bavel'.
