IMHO: There is a good chance that Lisp is pretty close to expressing "natural language" in code. I would argue that written text / prose is even a bad starting point. I'd rather think about having an UML Activity Diagram, add a way to add parameters / variables to it. Then visually imagine that you take away the full bubbles around the commands and just leave the sides. They look like brackets, right?

Now fiddle in a syntax for having parameters, maybe place them next to the text that describes what the program wants to achieve.

The next step is to define what the program or routine is actually doing, so think about step one again.

... Every time I think about a non-graphical way of writing a program as intuitive as possible I usually end up with some sort of Lisp.

EDIT: several edits for wording

"Any sufficiently complicated C or Fortran program contains an ad-hoc, informally-specified, bug-ridden, slow implementation of half of Common Lisp." - Greenspun's Tenth Rule