Given that we see the Greybeards and Parthurnax both write by shouting words into existence, could this be considered the traditional form of writing the dragon language?
What I was saying was that in canon, they would probably write it out, the whole "shouting words into rocks" thing was probably just to save time and money on making more animations for such things.
If I had enormous, sharp claws, I would be carving things into stone all the time. To me, that seems easier than screaming whenever I needed to add something to my To Do list.