Controlling a dc motor with a saved text file, is this possible?

the program code would convert every letter into it's ASCII value and that value would drive the motor at that speed.

your program already has the ASCII values done for you.

char myText[] = "The Cat in the Hat" ;

if you look at

myText[0]
myText[1]
myText[2]

as (byte) not (char) you'll see the ASCII codes