I used Forth professionally on a number of processors over about ten years. On a couple of them I had to implement the language from scratch, including having to write a code editor and other system tools.

Remembering those days always makes me smile. I really enjoyed that work. The language is fun to use, fast to code and execute and as flexible as you want it to be. I made extensive use of it in robotics, including designing and building a networked multiprocessor walking robot controller from scratch. Remember, no Internet, Arduinos or SO; just bare chips, data books and your own creativity.

My first Forth project was on a 6502.