Really young, according to the Manhattan Institute's Sol Stern.
What all conscientious teachers ought instead to try to inculcate in students is "literacy for social equity and social justice," a literacy that can deconstruct language and show how it is used to maintain power and privilege in our current society.
These are the views of Brian Cambrough, a professor in New South Wales and a leader of the "whole-language movement." Cambrough's wisdom plays a dominant role in a new New York City public school how-to-teach-reading campaign.
Another unscientific theorist involved is Lucy Calkins, a professor at Columbia's Teachers College. Stern on Calkins:
As I pointed out in "Breaking Free," her approach to teaching reading and writing to young children is based on the Romantic idea that all children are "natural readers and writers" and should be encouraged to start scribbling in journals and rewriting composition drafts without worrying or being taught much about formal grammar or spelling. Under Ms. Calkins's tutelage, the city's new literacy curriculum encompassed two of progressive education's key commandments -- that teachers must not "drill and kill" and that children can "construct their own knowledge."
Or they can actually learn to read.
Pity the "liberated" schoolchildren. Those with dedicated parents will learn to read at home -- because they certainly won't get the instruction at school.