We know that it evidently walked rather than slithered on the ground. The slithering was a product of the curse or judgment of God, but I would seriously question its ability to talk and communicate as do humans before it became an instrument of Satan. Talking and reasoning in language is part of the original created differences between man and animals. This special work of God in man's creation is surely designed to stress the great difference between man and animals which would include the ability to reason and communicate with words rather than just sounds. While animals can communicate to some degree with each other and with human beings, they do not possess the ability to reason as do people nor to express themselves as such.
Language is unique to people.
You can train your dog to go get the paper, but you cannot sit down and discuss its contents with him. Actually, Eve should have immediately been wary of such conversation, but she was evidently taken by surprise. In Genesis 1 we are told Adam and Eve were to keep and care for the garden. At any rate, I don't think we can assume the serpent could talk before it became an instrument of Satan. All rights reserved.