Ahh, but the goal is to find another language with "such a broad chasm between two versions of the language." It seems I can't win if people decided that my examples are so far apart that they are no longer two versions of the same language. ;)

What about Old S v.s New S? S v.s S4? S vs. R?

What about D1 and D2 of the D programming language?

Classic awk vs. nawk?

Honestly, I could go on. I think the person I'm responding to really doesn't know much about programming language histories.