I’d like to write an sf novel written in Egyptian (late period) hieroglyphics.
I spent much of my early life creating my own languages, and during that time as I was studying enough to attempt something like that, I examined very deeply many other languages and writing systems*.
I attempted to learn to read and to write late Egyptian hieroglyphics as well. I did that for about two years, and it is much harder than any currently extant human writing (or reading) system. Those are relatively easy for me. Hieroglyphics not so much.
Even at the height of my learning I could only accurately decipher — after much effort — 20% of even the simplest writing.
But if I had infinite time on earth, I really would learn it and then write an entire sf novel that way just for my own amusement.
Now that would be cool.
*Which let me tell you is so so much harder in a hick town pre-internet with basically no real library and no transportation, as compared to now. When I look back at what I was able to achieve with basically no resources and so many people even in my own family actively, violently hostile to me, I’m frickin’ amazed. Go early me!