"For one thing, it can also tell you about the history of the word, its origins and its evolution. Not all languages have this property in their written forms, but English does" (English Language & Usage).

It can also serve to create heterographs out of homophones, which helps when reading. For example, consider the word pronounced /raɪt/. That can be any of:

wright
right
write
rite

As soon as you see it on the printed page, you know which of those four words it is. You don’t have to puzzle it out. This increases reading speed and proficiency.

The other largely unsung reason for how English spelling helps you is because if you actually spelled things the way people said them, no one could ever read anything anyone else ever wrote! Well, nobody outside their own current dialect — if that.

I don't think I'd ever seen the word "heterograph" before. It's not even in the OED...



... but the word is immediately understandable, because it's written in the style we're used to in English.

By the way, "heterography" is defined in the OED as "Spelling that differs from that which is correct according to current usage; ‘incorrect’ spelling" — as in "There is a pretty general consensus that unconventional spelling or heterography is bad spelling." But Wikipedia says: "In linguistics, heterography is a property of a written language, such that it lacks a 1-to-1 correspondence between the written symbols and the sounds of the spoken language. Its opposite is homography, which is the property of a language such that written symbols of its written form and the sounds of its spoken form have a 1-to-1 correspondence."