No, pirates don't say "Aaaaargh!" Charlie Brown says "Aaaaargh!" Or is it Linus? I'm pretty sure it's not that bitch Lucy.

Pirates say "Aaaaarrrr!" No "gh" on the end. They say "Aaaaarrrr!" because it's as far as they got in learning their alphabets. "Esssss" was just a little too advanced for them.