Alright, alright, there's no need to be defensive over it.

I take back anything that was wrong, but I won't take anything back that was relevant to the discussion.
Given time, I'm sure down the track this would be debunked or declared as something else. For an example: Jesus preformed miracles, now 2000 years later we have the 'Jesus myth', declaring he never existed to begin with.
Now, the question is, when God speaks, is it external or internal?
Though God is capable of both, speaking externally is the exception, not the rule. In Christianity, God has chosen to speak to the masses through the bible as according to scripture:
Isaiah 55:11
2 Timothy 3:16 - 17
To be honest, I think it would bring about even more confusion. If God were to speak audibly, what should he say? What would you want him to say? Every individual has their own questions and their own doubts that needs to be addressed. A written word has more of a chance of successfully achieving that purpose. I don't have a problem with God declaring himself audibly, but Christians have to respect why he does or doesn't. After you hear him, next you would want to see him, after you see him, he must prove himself by remaining seen, to prove his divinity he must preform more and more extravagant miracles to satisfy etc. Though a simple request, God then becomes a servant rather than a master. God has already demonstrated his humility through Christ. Faith in his word (for the Christian) cuts right through these expectations.
Or as C.S Lewis put it:
I gave in, and admitted that God was God.
I should of explained this right from the first post...