Cap'n Yellowbeard's glossary:
Turning on account = turning pirate.
Splice the mainbrace = to have a drink (usually more than one).
Scurvy = (1) A deficiency disease which often afflicted sailors; caused by lack of vitamin C. (2) A derogatory adjective.
Hornswaggling = cheating.
Sprogs = untrained recruits.
September 19th is in fact International Talk Like A Pirate Day, in addition to being Kate's birthday.