Me realizing that festival uses a Lisp dialect:

Oh cool, I can add accessibility features to my Emacs stuff by procedurally generating the code in elisp.

Me realizing that festival's symbols are case sensitive:

Welp, I guess I can just do

(defun festival-saytext (text)
  (format "(SayText %S)" text))

and do the rest of the processing in elisp directly. That's probably all I wanted anyway.