A friend of mine wanted to check the speed of Julia vs a compiled language like C++ or Fortran. So he wrote a simple routine in Julia to invert a matrix. Then he compiled a Fortran code to do the same. Compiler flags were all set for maximum optimization and the function was using the LApack routines for matrix inverse. The Julia code still won by about a factor of 10. (I haven’t done this myself so I can’t verify the results. ) I’ve shared this with colleagues who are not yet convinced they should learn Julia and inevitably they counter my story with the question: if Julia is so fast precisely because it used compiled code how can it outperform a compiled language? That’s where I get stuck.