Arr, ye not ready to speak pirate? Then read this:
Double up on all your adjectives and you'll be bountifully bombastic with your phrasing. Pirates never speak of "a big ship", they call it a "great, grand ship!" They never say never, they say "No nay ne'er!"
Drop all your "g"'s when you speak and you'll get words like "rowin'", "sailin'" and "fightin'". Dropping all of your "v"'s will get you words like "ne'er", "e'er" and "o'er".
Instead of saying "I am", sailors say, "I be". Instead of saying "You are", sailors say, "You be". Instead of saying, "They are", sailors say, "They be". Ne'er speak in anythin' but the present tense!
These be tips, I be findin' for ye. I don't be ownin' them. Of couse they be known, so this be a review, aye?