From Doing our Own Thing, by John McWhorter:
Language is exactly like singing and dancing. Printing and the spread of literacy happen to have created a First World in which the written version of language infuses our very souls, in a way that musical transcription only does for a few, and dance transcription for even fewer. But properly speaking, that is a historical accident. The capacity for language that we are, most likely, genetically specified for is an oral one. Just as we have no genetic endowment for driving, although many of us do it daily, we have no genetic endowment for reading (which in fact damages our eyes) or writing (which is hard on the hands and, on keyboards, now gives millions carpal-tunnel problems).
In fact, most of the 6,000 languages in the world remain, for all intents and purposes, exclusively oral in their usage. Of course by now most of them have been transcribed onto paper in some way--brief word lists in some cases, longer word lists and short grammatical descriptions in many others. For hundreds of languages there are these plus, say, Bible translations and some transcriptions of folktales. But even in these cases, the very sight of the language on the printed page is something of a novelty for its speakers, commonly evoking a certain marvel and gratitude. For them, the language remains fundamentally oral, used causally at home or with friends. They rarely read it, especially since there is so little to be read--no newspapers, magazines, or novels. How deeply can a word list permeate daily life? Few of even us speakers of written languages are given to curling up with a dictionary and a cup of hot cocoa on a blustery night. Speakers of oral languages commonly use one of the world's "big" languages for reading and writing.
But these "Berlitz" languages are very much the exception among the 6,000 Only about two hundred languages are regularly taught in writing to children, and only about half of them are represented by piles of works on a wide range of subjects to the extent that we could say that they have a literature. For most of the languages in the world, if you learn it, it'd better be in order to talk to its speakers, a lot--because there's barely anything to read. Language is talked. If it's written, that's just an accident.
Is it really true that we've no genetic facility for reading? How come some kids learn to read so much faster than others, then?
Anyway, the book is fascinating so far. Highly recommended.