DECIUS BRUTUS: Great Caesar,
CAESAR: Doth not Brutus bootless kneel?
CASCAL: Speak, hands for me!
CASCA first, then the other Conspirators and BRUTUS stab CAESAR
CAESAR: Et tu, Brute! Then fall, Caesar.
For some reason, the last part of the phrase is always left out when discussing Caesar's death. It is very widely believed that Et tu, Brute? were the last words of Caesar*, and is often used as a joke in common speech. Even Wikipedia ignores the last part, and has an entire page on Et tu, Brute? with no mention of the subsequent phrase.
The reason I bring it up is that I think it brings up a different interpretation of the sentiment Shakespeare was trying to convey. "Et tu, Brute?" sounds like an accusatory statement of betrayal, similar to "how dare you!" Even Wikipedia mentions this interpretation:
It has been argued that the phrase can be interpreted as a curse or warning
On the other hand, the addition of "Then fall Caesar", at least in my opinion, makes it sound more like a disappointment - similar to "how could you?" In a sense, Caesar believes that the fact that Brutus has taken the side against him is reason enough for Caesar to not fight back against his impending death. This is, of course, my interpretation.
Nonetheless, I don't understand why the second part of the phrase is never mentioned, even in literary discussions. Is it just because Latin sounds cooler?
(To be clear, I'm talking about the Shakespeare version of the story, and not the actual series of events. There's some evidence to suggest that Caesar's actual last words may have been "And you, son?" (translated), but that doesn't change the point of the question.)
*From my personal experience. Depending on where you live and who your friends are, this might not be the case.