Just replying to one of my older posts to retract an incorrect statement:

"There is not a large body of material written about #Forth".

I was absolutely incorrect. There is a LOT written down. You just have to dig for it a bit. It's in books and papers, and personal webpages, and places like the #simtel archive. And most of it is pretty old.

I think the other point stands -- Forthlikes have strong structural similarities, and a lot of behavior inevitably falls out of a short set of rules.