This is one of the things I love about new players. They ask questions like that. Sure there have probably been dozen of articles already written about the subject I mean since there’s been a Thief Class, there’s been Thieves’ Cant. All that stuff that I had read years ago just didn’t pop into my head when I was asked. So I let a little instinct and logic step in and come up with sort of good explanation.
First (according to Wikipedia anyway), the concept is based on reality. As spoken language, I imagine it to use “Common” but with meanings of some words changed as well as disguised much like rhyming slang. So the individual words may recognized by the uninitiated but their true meaning or their context won’t make any sense.More detailed meaning is gleaned from context and the use of hand gestures or sign language.
So yes a language with somatic components. It can be used to communicate covertly while others are listening to better disguise what exactly is being communicated. Plus it’s really handy when you’re sneaking around and trying to be quiet. You know like in every movie you’ve ever seen with commandos in it.
And what about a written form? Why, yes of course. Once again let’s dig into the world and there it is Hobo Signs. Thieves don’t want to leave behind incriminating evidence but it is a matter of professional courtesy to leave little bits of information behind to warn or aid the next thief who comes along.
So there you go. A little about Thieves Cant. Now go out and kill a monster and take its stuff.