Hmm... those symbols... will we ever have answers? Will we ever know what they mean? (Nope.) I've included here an appendix for easy access and analysis of the symbols. It isn't quite a dictionary since we have so few translations, but maybe someday. :)
For now, if you'd like to further analyze them, there are often lively discussions on the FanForum Roswell message boards. Check out the "Liz's Importance in the Alien Mythology" and the "Signs & Symbols... & Behr... Oh My!" threads. Many of these threads are archived at Maxcedo's site: Roswell Sci-Fi Theories.
The following are symbols appearing in Roswell episodes. The translations within trailers were part of the actual trailer. As you can see, not all of the trailer translations are consistent with one another. Because the trailers were approved by the producers, we can only then come to the conclusion that there is no standard "Antarian" language and the producers are making it up as they go along. This, of course, proves frustrating for all of us as we have been trying to decipher the symbols since the beginning and, I guess, for naught.
Departure translation of Alien Book:
You are the Royal four. Zan the king. Ava his queen. Vilandra his sister. Rath his councilor. You were created from the genetic material of your alien predecessors and human subjects. You were given human form so that you could live safely on the planet undetected until the time comes for your return. You have been given the granolith, a transport between this planet and Antar. You have also been given communication technology which will allow you to access information from your true home. The chamber containing your hibernation pods and the granolith has been hidden away from human settlement. It can only be accessed by the four of you. You have been provided with a guardian who will protect you from danger and keep you hidden from your enemies, both human...
I'm sure you all realize that the above translation is suspect. Alex translated it, but it was in the hands of Tess, the murdering and lying witch. Tess could easily have manipulated it before it came into the hands of Liz, Maria, and Michael in the episode: "Baby, It's You" S2E19. And for that matter, why didn't Tess just ask Alex to translate it. Afterall, Alex was a friend of the pod squad and I'm sure he would gladly have tried if it was asked of him. So why all the manipulation, mindwarping, and eventual death? Hmm...
Symbol 10 and 9
"Pod Chamber or Granolith"
This is the clue Alex left for Liz that everything was not right. It was his "signature" on the delivery Thai food receipt. At the time, everyone thought that the numbers had to stand for something and they looked an aweful lot like binary code. So there I was calculating binary, 7 bit characters, 8 bit characters, ascii, ebcdic, octal, hexadecimal, and so on. What you see above is just the beginning of the calculations and mutterings. Needless to say, the writers were never that clever and the clue was just meant to make Liz look through Alex's computer files.
Season 3 credits translation.
Translation appearing in the "How Far" trailer pre-season 3.
Translation appearing in the "Older, Braver, Wilder" trailer pre-season 3.