Corrected entry: Throughout the films only C3PO can understand R2D2 and has to translate for the other characters on many occasions. During the flight from Hoth to Dagoba Luke read a little screen with the translations of what R2D2 is saying. Then when they reach the planet and are both stood on the edge of the swamp Luke can miraculously understand what he is saying.
Star Wars: Episode V - The Empire Strikes Back (1980)
81 corrected entries
Directed by: Irvin Kershner
Starring: Harrison Ford, Frank Oz, James Earl Jones, Mark Hamill, Alec Guinness, Carrie Fisher, Anthony Daniels, Billy Dee Williams, Kenny Baker, Peter Mayhew, David Prowse
Genres: Action, Adventure, Fantasy, Sci-fi, Star Wars, Thriller
Continuity mistake: In the original 1980 version, in the first wideshot of Darth Vader's Star Destroyer, the light of a Star Destroyer can be seen on the right side just flying through space. This is fixed in the 2004 DVD release.
Darth Vader: Obi-Wan never told you what happened to your father.
Luke Skywalker: He told me enough! He told me you killed him!
Darth Vader: No. I am your father!
Trivia: The Special Edition covers of Return of the Jedi and Empire Strikes Back are wrong. The picture of the Emperor on ESB cover is from 'ROTJ', and the lightsaber duel between Luke and Vader on the cover of ROTJ is taken from 'ESB' (notice Luke is in his fighter pilot suit, and Vader is fighting him one-handed)
Question: Is there any reason why Luke believes what Darth Vader says when he tells him that he is his father?
Answer: The vision Luke sees in the cave on Dagobah is a clue to this. Luke is realizing he has a lot more in common with Darth Vader than the idealized father he'd always imagined. When Vader tells him he's his father, Luke doesn't want to believe it, but he simply can't deny that it feels much more true that his father would be someone passionate and reckless like himself rather than someone who exemplifies a noble Jedi, which feels like an obvious myth in hindsight.
Correction: The screen isn't translating, it's just a way for R2-D2 to communicate with Luke - he's outside the cockpit, after all.