What does David say to the Engineer?

we can only assume for now that he was asking the Engineer if he could make Weyland Immortal ? or something along those lines. He could of course have had his own agenda and asked the Engineer if he could make David human ? Hopefully we find out more in Prometheus II.

Well its left unexplained.... So every one can only assume... I would say that David would have said along the lines (well include these). "We have found the star map you left us and we come here to seek our creators and to wonder why you created us, we wish to learn more from each other." If the Engineer can read Human minds, he would already know and understand what Weyland was saying to him, this would be something more upsetting. The Engineer took a interest to David, held his head for a while, i assume he somehow realised that David was different and then realised he was not Human.

So, I wasn't anti-hallucinating, I didn't forget some AMAZINGLY RELEVANT DIALOGUE between David and the Engineer. WE REALLY DON'T KNOW WHAT WAS SAID? This 'secrecy of David' is the thing that most annoys me.

and WHAT WAS CHASING THE ENGINEERS 2,000 years ago? What???????????????????????

I think you guys are underestimating David's ability to have his own motives. He said he wanted Weyland dead. I'm pretty sure since he was being so secretive through the whole movie, he would be entirely capable of saying something along the lines of, "They're here to kill you." to ensure his "creators" died and he'd be free. I do hope someone comes up with a real translation soon.

David is inquisitive, throughout the piece he shows evidence of having an agenda, to understand better the motivations of creators and their subsequent apathy. I think he asks "Who created you?" or "Why did you create them?", at which point the engineer realises that his creation (man) has begun to play god (he examines david and pulls his head off in disgust/envy).