Right after they wake the surviving Engineer from stasis there is a bit of an argument about what to ask it. Did David ask Mr. Weyland's question? Elizabeth's? Something else? Is there any way we can know?
Edit: Now we know. In an interview revealed at Total Film with Dr. Anil Biltoo:
Well, according to Dr. Anil Biltoo, the film’s official translator and linguistics consultant, David did as he was asked, translating his words as follows: “This man is here because he does not want to die. He believes you can give him more life.”
The rest of the text of this article stands unedited except for the interview inserts, in italics.
We are forced to reconcile the reaction of the Engineer with:
- His/it's original mission, to destroy the Earth.
- His/it's momentary pause as it analyzes the situation upon awakening
- His/it's decision to kill the team and continue its primary mission.
Does David betray his creator? His pathological hatred of all of humanity is obvious to us, but not necessarily to them. Would he use the opportunity to ask a different question than he was asked or would he comply out of duty (or programming). My suspicion is David asked exactly what he was told by Weyland. Not that it mattered, the Engineer answered only with his actions to kill the team.
My supposition still stands and is supported in the rest of the Total Film interview review:
So there we have it. David wasn’t up to anything sinister, it just turned out that the Engineer wasn’t best pleased to be interrupted by a member of the species he was charged with destroying. Apparently, the scene was initially written to involve a much longer conversation, so perhaps more details will emerge in the deleted material on the DVD. Or even in a sequel...
Why wouldn't David say what he had been asked to? He is not concerned with the question or the answer. For him, it is academic at best. He has already made his decision about humanity and given the information he has up to that point, he assumes the Engineers already have their own less than stellar opinion of humanity as well.
However, given the purported intelligence of the Engineers, and a time-table of their last visit (approximately 2,000 years ago, during a very warlike period on Earth) once he saw how violent, humanity had remained, he realized he would have to complete his mission. He did not seem conflicted in any way.
My suspicion was he recognized what David was and could extrapolate how long he had been asleep, which may have given him greater motivation to deliver his payload, fearing a galactic outbreak of this violent species. The Engineer did not seem surprised to see us, likely as a diminutive and less impressive form of itself.
I had the impression the Engineer did not fear humanity, so much as their lack of individual control. He was privy to, in a matter of seconds, hierarchical dominance behavior, aggression, anger, and directed violence. From the aspect of a species that creates life, certainly an undesirable outcome. Perhaps the same reaction we might have if a beloved pet suddenly attacked us. We would put it down, for its own good. The Engineer maintained a surprising level of apparent emotional control during his attack on the team and his subsequent launching of his ship. He did not appear to have any issues with completing his mission, so his belief in the necessity was apparent in his actions.
I would also have to credit this Engineer with some degree of forethought. He was the only one on this ship to make it back to stasis and secure himself before the pathogen was able to reach him. I suspect he thought it would be safer to be in stasis than dying in the halls.
David's experience of humanity soured him on meeting the Engineers and even though he was intellectually curious about their technology, he showed no real interest in the Engineers, themselves, likely considering them as potentially dangerous as he considered mankind. Maybe moreso, since humanity was based on their DNA. If he did give the Engineer an account of what happened or how they came to be here, rather than Wayland's requested information, I am certain, he was surprised with his/it's reaction. It was certainly not an expected outcome from David's perspective.
Here is a recent io9 interview claiming to be the ultimate guide to all Prometheus questions.
What David said to the Engineer is not what set him off. It's not until he touches David's head (in other words, notices that he's an android) that he flies off the handle.
Remember, the whole theme of the movie is the tension between the creator and his creation, whether it is the Engineer and humans, mankind and robots (David), or parents and their children (Weyland and Vickers). While there is truth to David's statement that children can't wait for the death of their parents, at least in the sense that they can then surpass them, superiors tend to want to stay in power. Once the Engineer realizes humans have become creators (gods themselves, just like young Weyland says in the promo video), thus worshiping themselves, he knows he must punish/destroy them, as Zeus did to Prometheus.
In all likelihood, David told him exactly what Weyland asked. He was a pretty smart android and probably knew in advance how the meeting was going to go...
I managed to track down the [the real-life linguistics consultant used for the film who taught Michael Fassbender the dialogue], a Dr. Anil Biltoo of the SOAS Language Centre in London, to see if he could shed some light on the mysterious final scene.
He was most helpful and provided the following:
The line that David speaks to the Engineer (which is from a longer sequence that didn’t make the final edit) is as follows:
/ida hmanəm aɪ kja namṛtuh zdɛ:taha/…/ghʷɪvah-pjorn-ɪttham sas da:tṛ kredah/
A serviceable translation into English is:
‘This man is here because he does not want to die. He believes you can give him more life.’
I think David said something like the humans have come here to capture and study you which caught the engineers attention causing it to defend itself. Before David spoke the engineer showed no signs of aggression and also David said don't all humans want to kill their parents (or something along those lines) which showed David knew the humans probably planned on killing the engineer. I think David admired the engineer and decided to warn it of what the humans have came and found it for. The engineers probably never planned on destroying earth and humans in the first place they were unable to go back to earth to see how humans were doing because of the alien outbreak on the ship but the humans assume that the engineers had abandoned them.