What is the meaning of "Ein Kehah l'Shivrecha"?
Rashi: No one is pained over your breakage, for all rejoice. Kehah is an expression of something dim.
Radak: Kehah is a cure, like "Kehah ha'Nega" (Vayikra 13:6). It is contracting and stopping - when a plague or breakage is about to heal, the surrounding skin wrinkles. The verse addresses Melech Ashur, mentioned above.
Malbim: No man's Ru'ach is weak on him and he is pained over your breakage. '
What is the meaning of "Nachlah Makasecha"?
Radak: The verse uses Nif'al conjugation for the wound, even though it acts. It makes the person ill! Nif'al is used, for the wound is the object of the first cause. We find similarly "Ki Chalah v'Necheratzah" (Yeshayah 28:22), "Ki Chalah Af Nivhalh" (Tzefanyah 1:18).
Malbim: Also the wound after the breakage, no one is pained over you.
Who are "Kol Shome'ai Shim'acha"?
Malbim: All who hear of your breakage.
Why did they clap hands?
Rashi: It was to rejoice. Radak - this is like "va'Yaku Chaf va'Yomeru Yechi ha'Melech" (Melachim II, 11:12), Malbim - because you constantly did evil to all nations, they rejoiced over your fall.
