Wag the Director: Christopher Lee refused to speak any of the lines of his character in Dracula: Prince of Darkness because he found them terrible. This is why Dracula is silent in the entire film.
An oft-repeated yet oft-debunked claim. Screenwriter Jimmy Sangster has claimed in interviews and in his memoirs that Dracula did not speak because Sangster wrote no dialog for him, reasoning that Dracula-having just been reconstituted from his own ashes-was more mysterious and threatening by not speaking. Sangster also points out that despite Lee's apparent fondness for grousing about the Hammer Dracula films, he was perfectly willing to show up for a paycheck.
However, in an interview, Mr. Lee himself has said that this rumor is in fact true, and that the only reason he did any of those movies is that the studio blackmailed him by threatening to put a lot of people out of work if he didn't take the part.
Removed (see Repair, Don't Respond)