John Camden Hotten, The slang dictionary
“ Those who regard the London costermonger as a fearful being are very much mistaken,—he is singularly simple-minded and innocent, and has, indeed, very little to conceal; but he certainly does like to wrap himself up as in a garment of mystery, and sometimes believes that the few words of slang he knows, mixed as they are, and troublesome as they have been to him, form an impenetrable barrier between him and the rest of the world. He is fond of exhibiting what knowledge he possesses, and so talks slang in public much more than in private ”
