At this time in Eden, you are right in saying that Adam and Eve had not experienced death, but I think we need to give God some credit for his communication skills.

It is true that in the Bible’s precis of the story God seems to baldly announce the consequences in a way which could tempt us to think he hadn’t given them the full truth.

Here’s the reference, from Genesis 2 16 And the LORD God commanded the man, “You are free to eat from any tree in the garden;  17 but you must not eat from the tree of the knowledge of good and evil, for when you eat of it you will surely die.”

We need to realise that this story is a precis. It’s not untrue, but it doesn’t give every detail. It gives the general meaning of what God said, but there may have been much more communicated than the English phrase which comes down to us, or even its Hebrew original. It does not give us the fine detail about the way in which God communicated. We can presume that God did not even speak Hebrew to them at the time.

We are told that the God who is Truth, and his Son who is the Word, speak about dying. Would they speak knowing that his hearers had no concept of the meaning of the word?

Lesson 1 in any training on Communication Skills is always to communicate in language and concepts which are familiar to the hearer. Jesus is the classic example, he always used stories which held familiar themes to his listeners.

If he was so good when he lived on earth as Jesus, would he have been a total failure when he, as the Son, the Word, joined the Father to communicate with the Humans they had made?

My conjecture is that God communicated in concepts Adam and Eve could understand, In very simple terms, if he used their experience of being alive, then notified them of the possible end of that state, we could deduce that they would get a good general grasp of what was going on.