Shared with you
When Captain Salazar introduces himself to Henry Turner he says his name twice. Although it is not as evident the first time he says his name, nor anywhere else in the movie after the second, he pronounces it with the Spanish traditional pronunciation of "Salathar." When watching the mouth during the second time he says his name it's clear his mouth makes a "th" as in "think" motion. This is because in Spain the Z (and also the C) is traditionally pronounced with a "th".
The father of Captain Jack Sparrow was played by a Rolling Stone (Keith Richards), and in this movie, the uncle of Captain Jack Sparrow was played by a Beatle (Sir Paul McCartney).
This movie was being produced as Johnny Depp was going through a bitter divorce. He was chronically late to the set, to the point where it ate into the schedule as the set often came to a halt for several hours at a time. It got to the point where a production assistant was hired just to wait outside Depp's house and announce that he was awake when they saw the lights inside come on.
Although this movie was initially claimed to be the last one in the franchise, a sixth installment was announced after its release.
Because Will Turner (Orlando Bloom) is the Captain of the Flying Dutchman, he can only set foot on land once every ten years. This movie was released ten years after the third movie, which was the last one with Will.
(At around six minutes) Henry (Lewis McGowan) recognizes a ship as Bonnet's ship called "Royal James". Stede Bonnet was a real-life pirate who worked closely with Edward Teach, a.k.a. Blackbeard. Bonnet was active from December 1717 to December 1718 before he was hanged in Charles Town for piracy.