1)
Why does it say "Ya'anu"? He did not speak to them before this!
1.
Radak: Ya'anu can be the first words, like "v'Anisa v'Amarta" (Devarim 26:5), and the first "va'Ya'an Iyov" (3:2).
2)
Why do they say "Gam Atah Chuleisa Chamonu"?
1.
Rashi: They are astounded - how did evil come upon you, that you became ill like us, to die?
2.
Radak: Also you, even though in your lifetime you ruled over all of us, now we see that you became ill like us, and death occurred to you, like it did to us.
3.
Malbim: Since illness and death came upon you, this shows that you are a person, like us.
