What did He speak about the Nevi'im?
Rashi: They should rebuke you and make you return to the good path.
Radak: This is like El ha'Nevi'im (I spoke to them). Also "va'Yavo'u ha'Anashim Al ha'Nashim"(Shemos 35:22, is like El ha'Nashim). What could I do for them that I did not do, so they would not forget Me? What I did with your fathers, I spoke constantly with the Nevi'im to warn you. I gave visions for them many days.
Malbim: I wanted to get them to repent, therefore I made many Nevi'im. In the days of Achav there were many hundreds of Nevi'im, Talmidim of Eliyahu. They rebuked the nation.
Why does it add "v'Chazon Hirbeisi"?
Malbim: Chazon is a kind of Nevu'ah. He speaks with words and vision, and via likenesses and Meshalim.
What is the meaning of "uv'Yad ha'Nevi'im Adameh"?
Rashi #1: I appeared to the Nevi'im in several likenesses.
Rashi #2: I make likenesses of My words via Meshalim, in order to help the hearers understand them. Radak - e.g. "Kerem Hayah li'Ydidi" (Yeshayah 5:1), "Mechorosayich u'Moldosayich" (Yechezkel 16:3). It says b'Yad, for Hashem sent the likenesses and Meshalim via the Nevi'im.