Thank you, janSIy!
I have plenty of cash, but, like many millennials, don't own a credit card. I'll just order TKD from my local Barnes & Noble (and be sure to get the updated version).
Duolingo sounds like a lot of fun! I've also been checking out the YouTube videos to get a good feel for the *sound* of tlhingan Hol. Like how to pronounce the capital Q affricate, or the Nahuatlesque tlh sound.
Finally, I see that the body of the first message I sent was empty (!) and that my text was only readable as an attachment. I hope everyone could see my message (given that you responded to and quoted me, obviously YOU could).