In a 2015 interview, Tom Kenny said that the voice actors were given clearance to swear during recording, since it would be censored out. No one knows if an uncensored version exists.
In Sailor Mouth, if you look closely at the dumpster writing SpongeBob is reading, you'll see someone has written: 'Patchy was here.' This is an Easter egg to the live action role Tom Kenny (SpongeBob) plays; Patchy the Pirate, president of the SpongeBob fan club.
In "Sailor Mouth", Mr. Krabs says that there are 13 words you should never use. Squidward corrects him, "Don't you mean seven?". This is a reference to George Carlin's famous 1972 "Seven Words You Can Never Say on Television" monologue.
Although This Episode Premiered In 2001 It Was Made In 2000 According To The Credits