We know that development of Sumerian writing took at least hundreds, possibly thousands, of years. As we shall see, the prerequisites for those developments consisted of several features of human society the determined whether a society would find writing useful, and whether the society could support the necessary specialist scribes. Many other human societies besides those and early Mexicans – such as those ancient India, Crete, and Ethiopia evolved prerequisites. However, the Sumerians and early Mexicans happened to have been the first to evolve them in the Old World and the New World, respectively. Once the Sumerians and early Mexicans had invented writing, the details or principles of their writing spread rapidly to other societies, before they could go throughout the necessary centuries or millennia of independent experimentation with writing themselves
Blueprints and borrowed letters.
Guns, Germs, and Steel. Author Jared Diamond.