“Why do people have such a hard time with the thought of animals being able to use human speech?”
Consider Adam and Eve when the snake spoke to them. There is no indication that they were shocked at all by it speaking.
That's an excellent point.
Eve carried on a conversation with it and Adam watched and listened to the whole thing and there's nothing in the passage to indicate that this was unexpected to them.
I'd sure be suspicious if some animal came up to me and started talking to me, trying to sell me something....
But then again, there weren't used to used car salesmen and lawyers....;)