Long John Silver is clearly a master wordsmith. He can make nearly anybody believe nearly anything, at least for a while. But the spoken word is only one form of communication in Treasure Island. There's also the language of appearance, in which a sharp look demonstrates Captain Smollett's intelligence and a terrified shudder reveals a superstitious pirate's fear of ghosts. And then there is the language of the island itself: the map tells one story, but the shifting alliances and actions of the people on the island rewrite its geography (for more on this, see "Setting"). All of these languages – spoken, physical, and geographical – can also be deceptive. For a writer, Robert Louis Stevenson is surprisingly suspicious of the persuasive value of language.
Robert Louis Stevenson deliberately makes some pirate words and phrases too obscure to understand in order to increase the mystique of pirate society.
Even though Captain Smollett occasionally uses sea slang, his willingness to speak his mind against the wishes of his employer distinguishes him from pirate flatterers like Long John Silver.