It has several interesting properties. It is quite a rabbit hole, but a nice one to get lost into. I would say that the most interesting thing you should know

It has several interesting properties. It is quite a rabbit hole, but a nice one to get lost into. I would say that the most interesting thing you should know about them is that practically everything they do is manipulating a stack (actually, there are usually two stacks, I don't know if this is the case for Stabel). What I find more interesting about them is their simplicity (comparable only to Lisp), which makes possible writing a basic interpreter in only a few lines of code. Being more concrete, an important property of concatenative languages is that they allow a point-free programming style, which gets a bit to get used to but really makes you think in a different way. If you already feel curious, I would suggest the book "Starting FORTH" before looking into more modern (and practical) alternatives.