If you're talking about parsing speed, Dyalog is slow because it has a much more complicated grammar, and because it stores the execution stack in the workspace

If you're talking about parsing speed, Dyalog is slow because it has a much more complicated grammar, and because it stores the execution stack in the workspace in order to make stack overflows impossible. If you're claiming k or Forth is faster for large array processing, I'd like to see some benchmarks. Do you have a citation for Moore on the instruction cache?