Sometimes you see these efforts to "improve" FORTH by making it more like a traditional language (meaning, C+ava). One guy had control words. The problem is, all these things just add overhead and no real functionality. FORTH is alreadly very OOP-oid. You can use defining words that create entire black boxed data structures and return the address of it on the stack. You should NEVER need any basic stacks other than the data and return stacks, and arguably a floating point stack if the hardware supports it.

The issue of visibility should be handled with vocabulary contexts, not with a C++ like keyword. This misses the whole FORTH point of a strictly interpreted stream (threaded interpretation).