Arrr, mateys!
Since it was International Talk Like a Pirate Day on September 19, I wanted to share a couple articles on the origins of the pirate accent and some pirate terms and phrases.
The accent comes from actor Robert Newton, who grew up in Dorset, England, not far from where Long John Silver and Blackbeard were from (Bristol, England). Newton portrayed Long John Silver in the Disney movie Treasure Island in 1950, and Blackbeard in Blackbeard the Pirate in 1954. He used the West Country English accent for those movies. 
https://reference.yourdictionary.com/resources/pirate-terms-phrases.html