Martin Hewitt, Investigator by Arthur Morrison

It was comparatively rarely that Hewitt came into contact with members of the regular criminal class -- those, I mean, who are thieves, of one sort or another, by exclusive profession. Still, nobody could have been better prepared than Hewitt for encountering this class when it became necessary.

By some means, which I never quite understood, he managed to keep abreast of the very latest fashions in the ever-changing slang dialect of the fraternity, and he was a perfect master of the more modern and debased form of Romany. So much so that frequently a gypsy who began (as they always do) by pretending that he understood nothing, and never heard of a gypsy language, ended by confessing that Hewitt could _rokker_ better than most Romany _chals_ themselves.