# my servant will sprinkle many nations

The servant causing the people of the nations to be acceptable to Yahweh is spoken of as if the servant were a priest who sprinkles the blood of a sacrifice to make someone or something acceptable to Yahweh. 

# will sprinkle

The Hebrew word translated "sprinkle" here can also be translated as "surprise" or "startle," which some versions of the Bible do.

# many nations

Here "nations" represents the people of the nations. 

# kings will shut their mouths

"kings will stop talking" or "kings will be silent" 

# that which they had not been told

"that which no one had told them" or "something no one had told them"