Quenya. Preferably written in the Tengwar alphabet.
Sorry to burst your bubble, but we already have Quenya, just not in the Tengwar alphabet. Hmmm..... Mandalorian? I VOTE MANDALORIAN! OYA MANDA! I guess we could have iron armour be Beskar'gam, not sure about the rest though...
EDIT: Yes, my Darth Caedus picture finally kicked in! Now I can use the power of the dark side on those who disagree with me! Yes, I am using a Star Wars EU character as my profile picture to suggest a Star Wars EU language pack. Hmmm..... I really need to get some Beskar'gam.
Personally I just want English, but with enchantment roman numerals up to like 100 or something. As a custom map maker I find it really annoying when I try to make an almost invincible suit of armour, and it shows up in inventory as "Protection enchantment.level.20" or something.