I posted a small snippet on Twitter and got a really varying guesses as to who the speaker is. So here is a snippet and a poll to go with it. If the majority of people guess correctly, the mysterious speaker will be confirmed on Friday.
“Repeat back to me what I said.”
“You said not to go,” I intoned.
“And what did you do?”
“So you deliberately disobeyed me.”
PS. There is a clue in Magic Binds.