Netherese

"The world is bigger than we know. The world is also older than we know and ultimately far more unknowable than, well you get the point. There is too much out there for me to say definitively that this book represents the pinnacle of the greatest archaeo-linguistic challenge anyone has ever faced. However I like to humbly think it ranks pretty highly.
When Gadenthor crashed into the earth centuries ago, we had to grapple with a wide array of challenges. The formerly flying city was covered in the most intricate and powerful array of wards and protections ever seen before or since, and unravelling even the most basic of those would take our arcanists more than 100 years. Eventually though, though a shield still prevented us from getting too close to the city itself, we were able to peer over and at least see the ruins of this once great city, and we got our first sight of the most important thing to further everything that came after - their language.
Street signs, shop signs, books fallen open just within our line of sight - these were the tools that linguists had to use - held aloft either by their own power or the power of others, flying dozens of meters away and hundreds of meters in the air using telescopes and hastily scribbled notes to gather all pieces of language they could see. It was a remarkable endeavour just to gather the information - see but not touch, and even then only in the most precarious way. The arcanists agreed they could not penetrate that final shielding barrier until they understood the language the spell was written in and so all eyes turned to the linguists.
It took years. Not everything they could see was even written in the same language, and they had precious little text to work with. Road names are not exactly robust with syntax or grammar. Everything was cross-referenced over and over and great debates were held between scholars that ultimately turned out to be over an ink stain. Assembling the Netherese language from scraps, scrounged like ants hunting for seeds in a wagon bed, was an effort unlike any other. Now you can read this text and discover the language for yourself, neatly laid out and indeed mostly copied from an instructional treatise of their own that we eventually uncovered when the shield was lifted and we could search in earnest, more than two centuries after the city initially crashed, and the result of hundreds of people putting in hundreds of hours of work.
So when you say to your tutor that this language's alphabet is too difficult to remember, know that they will have no sympathy for you, and nor should they."
--Foreword to 'An Introduction to Netherese', translated from Orcish