Yeah Forth doesn't seem very good as a teaching language. Maybe the "first lesson" part where you're just showing how you can build a toy program from simple words would go well, but any nontrivial project where you have to start incorporating DUP and OVER and ROT and PICK and friends seems like a nightmare to teach to anyone who hasn't programmed before.

Kids need an antidote to the brain damage that is standard mathematical notation. I prefer lisps variadic prefix notation, but if you're just doing fixed arity functions without higher order functions than prefix and post fix are as good as each other, and you don't have the dreaded sea of parenthesis.

My kid was curious about my HP-35 and I taught them how it works. They got it in no time and I made it an exercise to rewrite math expressions in RPN.

Not sure they are that interested in programming, but FORTH is a little sweet language.

My first experience with it was Paul Lutus’ GraFORTH. On the Apple II it was ridiculously fast.

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