I guess it's too late now, given that the advent calendar is completed, but for next year:
159 karma · joined December 1, 2012
In fact, I think what you suggest would be an extremely short-sighted "strategy" for a consultancy. Sure, you might get the next contract working this way. But once the customer could get rid of you they would, and they would never hire you again.
The language is a simplified variant of Lisp. This is just a toy language, so a lot of things from a real Lisp will be missing, but I think there's enough to give you a sense of the core of the language. Actually, this version isn't too far off from the original Lisp written by John McCarthy over 55 years ago.
My suggestion: Just try and see how it goes. If you find it too overwhelming, don't worry, you can always revisit the concepts later.
I didn't write the tutorial with novice programmers in mind, so I can't promise everything will be explained as you need. But still, if you do try, I'd love to hear your experiences.