So I was browsing around the wiki looking at the images for the written language of Ascalon to see if any runes matched with the Elonian alphabet when I stumbled upon a lead language creators page. Mr Matthew Medina.
Here's the specific excerpt that caught my eye.
So in an effort to find out if the work of me and two of my guild mates and fellow loreites Gmr Leon and Konig Des Todes was all in vain I asked if he could provide a list of which languages were nonsensical. His reply wasAs Guild Wars has evolved so have the languages - so far I haven't seen that anyone has translated the 100 or so Canthan symbols. One word of caution though - not EVERY language in the original Guild Wars universe actually translates into anything - I believe I was the only artist on the team that actually made readable languages, so some of the runes, glyphs and scripts you see in the game will be just for "show"So with our current researched dashed it seems we have a whole new thing that has been brought to our attention. While this doesn't mean mean there is definitely only ONE left (Matthew is only human and he could be mistaken or misinformed) this IS a confirmation that there is a prop in EoTN just laying around waiting to be deciphered! In my opinion the first order of business should be likely places this prop could be. While exploring have YOU seen anything that would be a candidate? What places would you suggest. After we have a list of suggested places I think we should discuss organizing an expedition to scour Eye of the North. What say you?As far as I have seen, all of the languages that CAN be translated HAVE been translated. Ascalonian has it's own page here on the wiki, as does Canthan. The other languages you see will most likely be untranslatable. The specific example you cited is just such a prop - the scriptures of those banners and pillars are not developed languages, but simply aesthetic choices.
There is only one "language" that has escaped detection thus far, which I can understand being that it only appears on ONE particular prop in Eye of the North. And honestly, if anyone can find this prop, and decipher the text just based on that single piece of art, I might just have to send them something ultra-cool!