Allow me to brag about romforth (https://github.com/romforth/romforth) which I ported to the "3c" Padauk and can run on really small rom/ram microcontrollers. Caveats: - tested only on an emulator SDCC/ucsim_pdk, not on real hardware - given how small the ram is, there is no user dictionary but new words can be defined and tested using what the Forth folks refer to as "umbilical hosting".